Readability Firefox Extension
Readability is a Firefox extension to strip the extraneous cruft out of webpages and present you just the content you read. When you read an article on a major news site you can end up viewing a huge header, ads down the sides, links to send/blog/print, etc. Readability strips out the content and presents it to you in an easy to read fashion. Incredible.
Thanks to dria.org for pointing it out.