In NYC, there was a hackathon I attended a few years ago where everyone got the same problems (forget what it was called - comedy hackathon maybe?). It was about who could solve it fastest (or at all). Each problem was time-boxed, to be done in a short session, and as a team. They even had games (like Golden Eye) and other crazy social stuff (go out to 5 strangers at lunch time and make them say a binary string on video). We need more pure-tech fun hackathons like that IMHO.