I recently did a charity 3 on 3 tournament, and it could have been the easiest/most lucrative thing I've ever done reffing. We had 2 man crews on half court games, and in the finals, we put a 3 man on a half court 3 on 3 game. The players, especially in the late stages were pretty much college and even some current D1 players, so it was fun. Best thing was a free lunch and $150 game check for 3 hours work. Did I mention it was across the street from my place
The people were great and I hope to get asked to do it again in the future.