Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.922
diff -u -r1.922 common.inc
--- includes/common.inc	13 Jun 2009 19:28:57 -0000	1.922
+++ includes/common.inc	14 Jun 2009 02:37:06 -0000
@@ -347,11 +347,21 @@
  * Generates a site offline message.
  */
 function drupal_site_offline() {
+  global $base_url;
+
   drupal_maintenance_theme();
   drupal_set_header('503 Service unavailable');
   drupal_set_title(t('Site offline'));
-  print theme('maintenance_page', filter_xss_admin(variable_get('site_offline_message',
-    t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => variable_get('site_name', 'Drupal'))))));
+
+  $variables = array(
+    '[site]' => variable_get('site_name', 'Drupal'),
+    '[uri]' => $base_url,
+    '[uri_brief]' => substr($base_url, strlen('http://')),
+    '[mailto]' => variable_get('site_mail', ini_get('sendmail_from')),
+    '[date]' => format_date(time()),
+  );
+  $site_offline_message = variable_get('site_offline_message', t('[site] is currently under maintenance. We should be back shortly. Thank you for your patience.'));
+  print theme('maintenance_page', strtr(filter_xss_admin($site_offline_message), $variables));
 }
 
 /**
Index: modules/system/system.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.admin.inc,v
retrieving revision 1.156
diff -u -r1.156 system.admin.inc
--- modules/system/system.admin.inc	13 Jun 2009 19:28:57 -0000	1.156
+++ modules/system/system.admin.inc	14 Jun 2009 02:37:08 -0000
@@ -1727,8 +1727,8 @@
   $form['site_offline_message'] = array(
     '#type' => 'textarea',
     '#title' => t('Site offline message'),
-    '#default_value' => t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.', array('@site' => variable_get('site_name', 'Drupal'))),
-    '#description' => t('Message to show visitors when the site is in maintenance mode.')
+    '#default_value' => variable_get('site_offline_message', t('[site] is currently under maintenance. We should be back shortly. Thank you for your patience.')),
+    '#description' => t('Message to show visitors when the site is in off-line mode.') . ' ' . t('Available variables are [site], [uri], [uri_brief], [mailto], and [date].') . ' ' . t('uri_brief is uri without the preceeding "http://".')
   );
 
   return system_settings_form($form, TRUE);