Fresh from the clogged tubes of teh intarwubs…
"… is a comprehensive post filtering & template system. It allows the user to define a set of simple "Catches" (criteria) to be met by a post, and then have a set of "Actions" applied to the post. This plugin takes action whenever a Post is published inside of WordPress (including Posts coming in via XMLRPC). It can be used for many tasks, including creating your own mini plugins without ever having to leave your WordPress administration area." Nice.
"… will provide contextually search your WordPress blogs and then list the results based on relevance. By using a template file you can completely control the look and feel of the search results page. Additionally, the plugin will track the searches and allow you present a “search heatmap” of the most popular searches."