ExpressionEngine 1.x, ExpressionEngine 2
This extension changes the default graphics captchas into accessible (and more secure) question and answer pairs.
Post a comment to a blog post using AJAX so the page does not have to be refreshed.
AjaxPublish hooks into the publish page to prevent the need for a full page reload when saving an entry. This can greatly improve the performance and experience of editing content through ExpressionEngine.
Know who did what and when they did it. Audit Pro provides more detailed activity logging for the Control Panel, supports custom email notifications and searching log entries.