diff --git a/modules/aggregator/aggregator-feed-source.tpl.php b/modules/aggregator/aggregator-feed-source.tpl.php
index 6a684bd..f9cfa55 100644
--- a/modules/aggregator/aggregator-feed-source.tpl.php
+++ b/modules/aggregator/aggregator-feed-source.tpl.php
@@ -17,6 +17,8 @@
  *
  * @see template_preprocess()
  * @see template_preprocess_aggregator_feed_source()
+ *
+ * @ingroup themeable
  */
 ?>
 <div class="feed-source">
diff --git a/modules/aggregator/aggregator-item.tpl.php b/modules/aggregator/aggregator-item.tpl.php
index e9ad1e0..74b2284 100644
--- a/modules/aggregator/aggregator-item.tpl.php
+++ b/modules/aggregator/aggregator-item.tpl.php
@@ -16,6 +16,8 @@
  *
  * @see template_preprocess()
  * @see template_preprocess_aggregator_item()
+ *
+ * @ingroup themeable
  */
 ?>
 <div class="feed-item">
diff --git a/modules/aggregator/aggregator-summary-item.tpl.php b/modules/aggregator/aggregator-summary-item.tpl.php
index fcd57c7..f9199a5 100644
--- a/modules/aggregator/aggregator-summary-item.tpl.php
+++ b/modules/aggregator/aggregator-summary-item.tpl.php
@@ -13,6 +13,8 @@
  *
  * @see template_preprocess()
  * @see template_preprocess_aggregator_summary_item()
+ *
+ * @ingroup themeable
  */
 ?>
 <a href="<?php print $feed_url; ?>"><?php print $feed_title; ?></a>
diff --git a/modules/aggregator/aggregator-summary-items.tpl.php b/modules/aggregator/aggregator-summary-items.tpl.php
index 0e2133a..4a0551d 100644
--- a/modules/aggregator/aggregator-summary-items.tpl.php
+++ b/modules/aggregator/aggregator-summary-items.tpl.php
@@ -14,6 +14,8 @@
  *
  * @see template_preprocess()
  * @see template_preprocess_aggregator_summary_items()
+ *
+ * @ingroup themeable
  */
 ?>
 <h3><?php print $title; ?></h3>
diff --git a/modules/aggregator/aggregator-wrapper.tpl.php b/modules/aggregator/aggregator-wrapper.tpl.php
index 0c2f774..be36576 100644
--- a/modules/aggregator/aggregator-wrapper.tpl.php
+++ b/modules/aggregator/aggregator-wrapper.tpl.php
@@ -10,6 +10,8 @@
  *
  * @see template_preprocess()
  * @see template_preprocess_aggregator_wrapper()
+ *
+ * @ingroup themeable
  */
 ?>
 <div class="aggregator">
diff --git a/modules/aggregator/aggregator.module b/modules/aggregator/aggregator.module
index f247d26..b12cfa8 100644
--- a/modules/aggregator/aggregator.module
+++ b/modules/aggregator/aggregator.module
@@ -266,7 +266,12 @@ function aggregator_menu() {
 }
 
 /**
- * Title callback for aggregatory category pages.
+ * Title callback: Returns a title for aggregatory category pages.
+ *
+ * Path: aggregator/categories/%aggregator_category
+ *
+ * @param category
+ *   An aggregator category.
  *
  * @return
  *   An aggregator category title.
@@ -276,11 +281,11 @@ function _aggregator_category_title($category) {
 }
 
 /**
- * Find out whether there are any aggregator categories.
+ * Finds out whether there are any aggregator categories.
  *
  * @return
- *   TRUE if there is at least one category and the user has access to them, FALSE
- *   otherwise.
+ *   TRUE if there is at least one category and the user has access to them,
+ *   FALSE otherwise.
  */
 function _aggregator_has_categories() {
   return user_access('access news feeds') && (bool) db_query_range('SELECT 1 FROM {aggregator_category}', 0, 1)->fetchField();
@@ -425,7 +430,7 @@ function aggregator_block_view($delta = '') {
 }
 
 /**
- * Add/edit/delete aggregator categories.
+ * Adds/edits/deletes aggregator categories.
  *
  * @param $edit
  *   An associative array describing the category to be added/edited/deleted.
@@ -474,10 +479,11 @@ function aggregator_save_category($edit) {
 }
 
 /**
- * Add/edit/delete an aggregator feed.
+ * Adds/edits/deletes an aggregator feed.
  *
  * @param $edit
  *   An associative array describing the feed to be added/edited/deleted.
+ *
  * @return
  *   The ID of the feed.
  */
@@ -574,6 +580,12 @@ function aggregator_remove($feed) {
     ->execute();
 }
 
+/**
+ * Gets the fetcher, parser and processors.
+ *
+ * @return
+ *   An array containing the fetcher, parser and processors.
+ */
 function _aggregator_get_variables() {
   // Fetch the feed.
   $fetcher = variable_get('aggregator_fetcher', 'aggregator');
@@ -660,10 +672,11 @@ function aggregator_refresh($feed) {
 }
 
 /**
- * Load an aggregator feed.
+ * Loads an aggregator feed.
  *
  * @param $fid
  *   The feed id.
+ *
  * @return
  *   An object describing the feed.
  */
@@ -677,10 +690,11 @@ function aggregator_feed_load($fid) {
 }
 
 /**
- * Load an aggregator category.
+ * Loads an aggregator category.
  *
  * @param $cid
  *   The category id.
+ *
  * @return
  *   An associative array describing the category.
  */
@@ -709,10 +723,11 @@ function theme_aggregator_block_item($variables) {
 }
 
 /**
- * Safely render HTML content, as allowed.
+ * Safely renders HTML content, as allowed.
  *
  * @param $value
  *   The content to be filtered.
+ *
  * @return
  *   The filtered content.
  */
@@ -721,14 +736,14 @@ function aggregator_filter_xss($value) {
 }
 
 /**
- * Check and sanitize aggregator configuration.
+ * Checks and sanitizes aggregator configuration.
  *
- * Goes through all fetchers, parsers and processors and checks whether they are
- * available.
+ * Goes through all fetchers, parsers and processors and checks whether they
+ * are available.
  * If one is missing resets to standard configuration.
  *
  * @return
- *   TRUE if this function reset the configuration FALSE if not.
+ *   TRUE if this function resets the configuration; FALSE if not.
  */
 function aggregator_sanitize_configuration() {
   $reset = FALSE;
@@ -759,6 +774,7 @@ function aggregator_sanitize_configuration() {
  *
  * @param $count
  *   Items count.
+ *
  * @return
  *   Plural-formatted "@count items"
  */
diff --git a/modules/block/block-admin-display-form.tpl.php b/modules/block/block-admin-display-form.tpl.php
index 94b6104..17a15e4 100644
--- a/modules/block/block-admin-display-form.tpl.php
+++ b/modules/block/block-admin-display-form.tpl.php
@@ -21,6 +21,8 @@
  *
  * @see template_preprocess_block_admin_display_form()
  * @see theme_block_admin_display()
+ *
+ * @ingroup themeable
  */
 ?>
 <?php
diff --git a/modules/block/block.admin.inc b/modules/block/block.admin.inc
index 7169190..26523fe 100644
--- a/modules/block/block.admin.inc
+++ b/modules/block/block.admin.inc
@@ -6,7 +6,9 @@
  */
 
 /**
- * Menu callback for admin/structure/block/demo.
+ * Page callback: Attaches CSS for the block region demo.
+ *
+ * Path: admin/structure/block/demo/% (for each theme)
  */
 function block_admin_demo($theme = NULL) {
   drupal_add_css(drupal_get_path('module', 'block') . '/block.admin.css');
@@ -14,7 +16,9 @@ function block_admin_demo($theme = NULL) {
 }
 
 /**
- * Menu callback for admin/structure/block.
+ * Page callback: Shows the block administration page.
+ *
+ * Path: admin/structure/block
  *
  * @param $theme
  *   The theme to display the administration page for. If not provided, defaults
@@ -57,7 +61,7 @@ function block_admin_display_prepare_blocks($theme) {
 }
 
 /**
- * Form builder for the main blocks administration form.
+ * Form constructor for the main block administration form.
  *
  * @param $blocks
  *   An array of blocks, as returned by block_admin_display_prepare_blocks().
@@ -165,7 +169,7 @@ function block_admin_display_form($form, &$form_state, $blocks, $theme, $block_r
 }
 
 /**
- * Form submission handler for the main blocks administration form.
+ * Form submission handler for block_admin_display_form().
  *
  * @see block_admin_display_form()
  */
@@ -197,10 +201,9 @@ function block_admin_display_form_submit($form, &$form_state) {
 }
 
 /**
- * Helper function for sorting blocks on admin/structure/block.
+ * Sorts active blocks by region, then by weight; sorts inactive blocks by name.
  *
- * Active blocks are sorted by region, then by weight.
- * Disabled blocks are sorted by name.
+ * Callback for usort() in block_admin_display_prepare_blocks().
  */
 function _block_compare($a, $b) {
   global $theme_key;
@@ -240,7 +243,7 @@ function _block_compare($a, $b) {
 }
 
 /**
- * Form builder for the block configuration form.
+ * Form constructor for the block configuration form.
  *
  * Also used by block_add_block_form() for adding a new custom block.
  *
@@ -441,7 +444,7 @@ function block_admin_configure($form, &$form_state, $module, $delta) {
 }
 
 /**
- * Form validation handler for the block configuration form.
+ * Form validation handler for block_admin_configure().
  *
  * @see block_admin_configure()
  * @see block_admin_configure_submit()
@@ -459,7 +462,7 @@ function block_admin_configure_validate($form, &$form_state) {
 }
 
 /**
- * Form submission handler for the block configuration form.
+ * Form submission handler for block_admin_configure().
  *
  * @see block_admin_configure()
  * @see block_admin_configure_validate()
@@ -519,7 +522,7 @@ function block_admin_configure_submit($form, &$form_state) {
 }
 
 /**
- * Form builder for the add block form.
+ * Form constructor for the add block form.
  *
  * @see block_add_block_form_validate()
  * @see block_add_block_form_submit()
@@ -530,7 +533,7 @@ function block_add_block_form($form, &$form_state) {
 }
 
 /**
- * Form validation handler for the add block form.
+ * Form validation handler for block_add_block_form().
  *
  * @see block_add_block_form()
  * @see block_add_block_form_submit()
@@ -544,7 +547,7 @@ function block_add_block_form_validate($form, &$form_state) {
 }
 
 /**
- * Form submission handler for the add block form.
+ * Form submission handler for block_add_block_form().
  *
  * Saves the new custom block.
  *
@@ -609,7 +612,7 @@ function block_add_block_form_submit($form, &$form_state) {
 }
 
 /**
- * Form builder for the custom block deletion form.
+ * Form constructor for the custom block deletion form.
  *
  * @param $module
  *   The name of the module that implements the block to be deleted. This should
@@ -629,7 +632,7 @@ function block_custom_block_delete($form, &$form_state, $module, $delta) {
 }
 
 /**
- * Form submission handler for the custom block deletion form.
+ * Form submission handler for block_custom_block_delete().
  *
  * @see block_custom_block_delete()
  */
diff --git a/modules/block/block.module b/modules/block/block.module
index 920090f..a658ab9 100644
--- a/modules/block/block.module
+++ b/modules/block/block.module
@@ -16,27 +16,27 @@ define('BLOCK_REGION_NONE', -1);
 define('BLOCK_CUSTOM_FIXED', 0);
 
 /**
- *  Show this block by default, but let individual users hide it.
+ *  Shows this block by default, but lets individual users hide it.
  */
 define('BLOCK_CUSTOM_ENABLED', 1);
 
 /**
- * Hide this block by default but let individual users show it.
+ * Hides this block by default but lets individual users show it.
  */
 define('BLOCK_CUSTOM_DISABLED', 2);
 
 /**
- * Show this block on every page except the listed pages.
+ * Shows this block on every page except the listed pages.
  */
 define('BLOCK_VISIBILITY_NOTLISTED', 0);
 
 /**
- * Show this block on only the listed pages.
+ * Shows this block on only the listed pages.
  */
 define('BLOCK_VISIBILITY_LISTED', 1);
 
 /**
- * Show this block if the associated PHP code returns TRUE.
+ * Shows this block if the associated PHP code returns TRUE.
  */
 define('BLOCK_VISIBILITY_PHP', 2);
 
@@ -177,21 +177,35 @@ function block_menu() {
 }
 
 /**
- * Menu item access callback - only admin or enabled themes can be accessed.
+ * Access callback: Only admin or enabled themes can be accessed.
+ *
+ * Path:
+ * - admin/structure/block/list/% (for each theme)
+ * - admin/structure/block/demo/% (for each theme)
+ *
+ * @param $theme
+ *   Either the name of a theme or a full theme object.
+ *
+ * @see block_menu()
  */
 function _block_themes_access($theme) {
   return user_access('administer blocks') && drupal_theme_access($theme);
 }
 
 /**
- * Theme callback for the block configuration pages.
+ * Theme callback: Uses the theme specified in the parameter.
+ *
+ * Path: admin/structure/block/demo/% (for each theme)
  *
  * @param $theme
  *   The theme whose blocks are being configured. If not set, the default theme
  *   is assumed.
+ *
  * @return
  *   The theme that should be used for the block configuration page, or NULL
  *   to indicate that the default theme should be used.
+ *
+ * @see block_menu()
  */
 function _block_custom_theme($theme = NULL) {
   // We return exactly what was passed in, to guarantee that the page will
@@ -249,7 +263,7 @@ function block_block_view($delta = '') {
 /**
  * Implements hook_page_build().
  *
- * Render blocks into their regions.
+ * Renders blocks into their regions.
  */
 function block_page_build(&$page) {
   global $theme;
@@ -305,10 +319,13 @@ function block_page_build(&$page) {
 }
 
 /**
- * Get a renderable array of a region containing all enabled blocks.
+ * Gets a renderable array of a region containing all enabled blocks.
  *
  * @param $region
  *   The requested region.
+ *
+ * @return
+ *   A renderable array of a region containing all enabled blocks.
  */
 function block_get_blocks_by_region($region) {
   $build = array();
@@ -319,10 +336,11 @@ function block_get_blocks_by_region($region) {
 }
 
 /**
- * Get an array of blocks suitable for drupal_render().
+ * Gets an array of blocks suitable for drupal_render().
  *
  * @param $list
  *   A list of blocks such as that returned by block_list().
+ *
  * @return
  *   A renderable array.
  */
@@ -378,7 +396,7 @@ function _block_get_renderable_region($list = array()) {
 }
 
 /**
- * Update the 'block' DB table with the blocks currently exported by modules.
+ * Updates the 'block' DB table with the blocks currently exported by modules.
  *
  * @param $theme
  *   The theme to rehash blocks for. If not provided, defaults to the currently
@@ -428,9 +446,9 @@ function _block_rehash($theme = NULL) {
     ->condition('theme', $theme)
     ->execute();
   foreach ($database_blocks as $block) {
-    // Preserve info which is not in the database.
+    // Preserve info that is not in the database.
     $block->info = $current_blocks[$block->module][$block->delta]['info'];
-    // The cache mode can only by set from hook_block_info(), so that has
+    // The cache mode can only be set from hook_block_info(), so that has
     // precedence over the database's value.
     if (isset($current_blocks[$block->module][$block->delta]['cache'])) {
       $block->cache = $current_blocks[$block->module][$block->delta]['cache'];
@@ -498,6 +516,7 @@ function _block_rehash($theme = NULL) {
  *
  * @param $bid
  *   ID of the block to get information for.
+ *
  * @return
  *   Associative array of information stored in the database for this block.
  *   Array keys:
@@ -511,7 +530,13 @@ function block_custom_block_get($bid) {
 }
 
 /**
- * Define the custom block form.
+ * Form constructor for the custom block form.
+ *
+ * @param $edit
+ *   Associative array of information retrieved by block_custom_block_get() for
+ *   this block if editing an existing block, otherwise an empty array.
+ *
+ * @ingroup forms
  */
 function block_custom_block_form($edit = array()) {
   $edit += array(
@@ -553,6 +578,7 @@ function block_custom_block_form($edit = array()) {
  *     - format: Filter ID of the filter format for the body.
  * @param $delta
  *   Block ID of the block to save.
+ *
  * @return
  *   Always returns TRUE.
  */
@@ -569,7 +595,7 @@ function block_custom_block_save($edit, $delta) {
 }
 
 /**
- * Implements hook_form_FORM_ID_alter().
+ * Implements hook_form_FORM_ID_alter() for user_profile_form().
  */
 function block_form_user_profile_form_alter(&$form, &$form_state) {
   if ($form['#user_category'] == 'account') {
@@ -613,7 +639,10 @@ function block_user_presave(&$edit, $account, $category) {
 }
 
 /**
- * Initialize blocks for enabled themes.
+ * Initializes blocks for enabled themes.
+ *
+ * @param $theme_list
+ *   An array of theme names.
  */
 function block_themes_enabled($theme_list) {
   foreach ($theme_list as $theme) {
@@ -622,7 +651,7 @@ function block_themes_enabled($theme_list) {
 }
 
 /**
- * Assign an initial, default set of blocks for a theme.
+ * Assigns an initial, default set of blocks for a theme.
  *
  * This function is called the first time a new theme is enabled. The new theme
  * gets a copy of the default theme's blocks, with the difference that if a
@@ -653,7 +682,7 @@ function block_theme_initialize($theme) {
 }
 
 /**
- * Return all blocks in the specified region for the current user.
+ * Returns all blocks in the specified region for the current user.
  *
  * @param $region
  *   The name of a region.
@@ -665,7 +694,7 @@ function block_theme_initialize($theme) {
  *   empty to see how many columns are going to be displayed.
  *
  * @todo
- *   Now that the blocks table has a primary key, we should use that as the
+ *   Now that the block table has a primary key, we should use that as the
  *   array key instead of MODULE_DELTA.
  */
 function block_list($region) {
@@ -684,7 +713,7 @@ function block_list($region) {
 }
 
 /**
- * Load a block object from the database.
+ * Loads a block object from the database.
  *
  * @param $module
  *   Name of the module that implements the block to load.
@@ -712,7 +741,10 @@ function block_load($module, $delta) {
 }
 
 /**
- * Load blocks information from the database.
+ * Loads blocks' information from the database.
+ *
+ * @return
+ *   An array of blocks grouped by region.
  */
 function _block_load_blocks() {
   global $theme_key;
@@ -744,8 +776,8 @@ function _block_load_blocks() {
 /**
  * Implements hook_block_list_alter().
  *
- * Check the page, user role and user specific visibilty settings.
- * Remove the block if the visibility conditions are not met.
+ * Checks the page, user role and user specific visibilty settings.
+ * Removes the block if the visibility conditions are not met.
  */
 function block_block_list_alter(&$blocks) {
   global $user, $theme_key;
@@ -831,11 +863,13 @@ function block_block_list_alter(&$blocks) {
 }
 
 /**
- * Build the content and subject for a block. For cacheable blocks, this is
- * called during #pre_render.
+ * Builds the content and subject for a block.
+ *
+ * For cacheable blocks, this is called during #pre_render.
  *
  * @param $element
  *   A renderable array.
+ *
  * @return
  *   A renderable array.
  */
@@ -900,9 +934,9 @@ function block_flush_caches() {
 }
 
 /**
- * Process variables for block.tpl.php
+ * Processes variables for block.tpl.php
  *
- * Prepare the values passed to the theme_block function to be passed
+ * Prepares the values passed to the theme_block function to be passed
  * into a pluggable template engine. Uses block properties to generate a
  * series of template file suggestions. If none are found, the default
  * block.tpl.php is used.
@@ -954,7 +988,7 @@ function template_preprocess_block(&$variables) {
 /**
  * Implements hook_user_role_delete().
  *
- * Remove deleted role from blocks that use it.
+ * Removes deleted role from blocks that use it.
  */
 function block_user_role_delete($role) {
   db_delete('block_role')
@@ -991,7 +1025,7 @@ function block_admin_paths() {
 /**
  * Implements hook_modules_uninstalled().
  *
- * Cleanup {block} and {block_role} tables from modules' blocks.
+ * Cleans up {block} and {block_role} tables from modules' blocks.
  */
 function block_modules_uninstalled($modules) {
   db_delete('block')
diff --git a/modules/block/block.tpl.php b/modules/block/block.tpl.php
index c1025c3..2fede56 100644
--- a/modules/block/block.tpl.php
+++ b/modules/block/block.tpl.php
@@ -12,11 +12,12 @@
  * - $block->region: The block region embedding the current block.
  * - $classes: String of classes that can be used to style contextually through
  *   CSS. It can be manipulated through the variable $classes_array from
- *   preprocess functions. The default values can be one or more of the following:
+ *   preprocess functions. The default values can be one or more of the 
+ *   following:
  *   - block: The current template type, i.e., "theming hook".
- *   - block-[module]: The module generating the block. For example, the user module
- *     is responsible for handling the default user navigation block. In that case
- *     the class would be "block-user".
+ *   - block-[module]: The module generating the block. For example, the user
+ *     module is responsible for handling the default user navigation block. In
+ *     that case the class would be "block-user".
  * - $title_prefix (array): An array containing additional output populated by
  *   modules, intended to be displayed in front of the main title tag that
  *   appears in the template.
@@ -39,6 +40,8 @@
  * @see template_preprocess()
  * @see template_preprocess_block()
  * @see template_process()
+ *
+ * @ingroup themeable
  */
 ?>
 <div id="<?php print $block_html_id; ?>" class="<?php print $classes; ?>"<?php print $attributes; ?>>