Tom Says: Code something crazy every day!
Rails Day 2007: If it happened, I doubt it would get sponsors. It'll take a while to dispell some of the stench from Rails Day 2006—great idea, great prizes, amazing participation, poor execution. I do hope someone will try to keep the idea alive.
Update: Lo and behold, someone stood up to the task! Rails Rumble is, "in a similar vein to Rails Day," hosting a Ruby on Rails programming contest on September 8—9, 2007. This time, it's 48 hours, and the public gets to judge the entries. I will definitely participate, and I hope the administrators the best of luck with the difficulties of managing a contest of this scale!
Posted May 24, 2007, in the night. Updated updated Aug 15, 2007, in the late, late night: Newly-announced 48-hour Rails competition!.