wynno
wynno is a web app for seeing the tweets in your Twitter timeline that interest you, and skipping the rest.
wynno enables you to apply filters to your Twitter timeline. Filters are rules you define about the kinds of tweets you always want to see or never want to see.
UPDATE: wynno has been discontinued and is no longer active at https://wynno.com. You can read the source code for wynno at https://github.com/ihinsdale/wynno.