Along the same lines, NYC's Big Apps 2.0 competition is going on right now (<a href="http://nycbigapps.com/" rel="nofollow">http://nycbigapps.com/</a>). Not affiliated, but I went to NYTM last year where they demoed the winners and there are some interesting (and impressively large) datasets to play with. One of my favorites was the mobile app, CabSense, that crunched the TLC data to determine the best corners to catch a cab on depending on the time of day