A buddy of mine recently emailed me a link to a site called xkcd. It's "A Webcomic of romance, sarcasm, math, and language" by its own billing, and it's absolutely hilarious. If you hover the mouse over the image for a few seconds a little comment from the author will pop up, and they normally add to the hilarity. Read with discretion, however. Some of the comics contain fairly strong profanity and other things, but most of them are clean. Don't say I didn't warn you, though. Below is a list of my favorite comics. Don't forget to mouse-over!
And finally, one that you shouldn't read if you want to avoid the rude and crude aspect of the comic, but is funny anyway: http://xkcd.com/72/