Oh man, I just found a fun toy! Google Image Labeler. The Google team found a way to make labeling images fun. You are teamed up with another player at random, and then they show you a bunch of Google Images for the next 2 minutes and you both label them as fast as you can. You get points for every time you and your partner come up with the same label for an image.
Go ahead and try. When you have an hour or so to spare, that is.