Schools.Jacksonville.Com continues to be an awesome project that teaches our team so freakin' much. The PHP/SQL that powers it is flexible and evolving, and what it shows about creating an audience that's really into prep stats is unreal.
Two years ago we did a National Signing Day football database where we logged where all the football recruits were going. It was fine and dandy, but lacked a lot. "Meh!" would probably describe it best.