http://ebaumsworld.com - lots of funny pics, videos, and sounds (mostly prank calls and such)

http://maddox.xmission.com - a really funny guy who's pissed at the world

http://www.collegehumor.com - lots of funny stuff sent in by college students

http://www.somethingawful.com - not quite as great as the others, but still quite cool, check out the steal of the century videos especially

http://www.collegeuniversity.com - a great short flash series about 2 college students

http://www.homestarrunner.com - how can you not have heard about this? Crazy flash comic.. the strong bad emails are the best parts (or at least a lot of them)

http://www.dailyrotten.com - told this one by Fry, real news stories that are hilarious.. or so he says