http://www.mcsweeneys.net/ - very funny, browse through the "Lists" section if you get a chance
http://www.engrish.com/ - not extremely p.c., perhaps, but it's very funny
http://www.zefrank.com/ - funny, clever, skilled web design
http://www.mirrorproject.com - an interesting project. Amy and I have both submitted pictures.
http://antwrp.gsfc.nasa.gov/apod/ - "apod"- photos of where we live
http://www.westegg.com/simpsons/ - if you think you hate the Simpsons, here's where you can find out why you're wrong.
http://postsecret.blogspot.com/ - confessions of artistic people
Other compulsive sites:
The Daily Photo project - Lots and lots of pictures of the same person. Mesmerizing.