Michael I. Mandel, a signal processing grad student at Columbia, sent in a link to his latest project -- an online game of sorts in which participants listen to ten seconds of a randomly selected song and then describe what they heard with tags. If one of the words/tags used in your description matches that of someone else, you each earn points (2 points if you were the first person to use the tag to describe that song, 1 point if not).
I played around with it yesterday and only scored one point in 7 or 8 listens, which hopefully has more to do with the fact that the site has only been up for 10 days (with 150 or so participants) than with my music describing skills. As more people tag songs, hopefully those points will start racking up faster.
Mandel writes that the data will eventually be used in an automatic music recommendation generator:
You can give it a whirl at game.majorminer.com.