I have two picture sites that will help you waste lots of time. The first is ImgFave, which is a site of pictures that lots and lots of people have uploaded to share with each other. I've picked one at random that makes me feel happy, but there's anything you can think of (and lots of things you probably can't think of) to be found there.
The second site is a LiveJournal blog, RiotClitShave. It's photos collected by one user, thousands and thousands of them. They're unusual and frequently a bit dark, but most of them are thought-provoking and worth seeing. One funny one that I've saved is this one, which is living proof that you shouldn't piss off the anteater.