Sidebar blocks contain all sorts of nifty stuff, but sometimes you want to include or embed that stuff into the body of your node. Instead of using PHP snippets (a possible security hole on public sites), you can use this module. When it's activated...
[block:name of module=delta of block]
...will insert the contents of a rendered sidebar block into the body of your node. If no delta is specified, the default block for that module will be displayed.
Important Security Note: By design the Insert Block module has historically not supported block role settings. Inserted blocks were visible to all users. Role checking support was recently added to Insert Block (see http://drupal.org/node/1227982). Please be safe and make yourself aware of the new settings, as detailed in the Security Note in the updated README.txt.