I saw that Ryan North and Company were doing something with this in a newspost on Dinosaur Comics some time ago, but I just today looked at it.
What is it, you ask, faithful and often disappointed reader? It is the Death Machine. And this site describes the rules and soforth for submitting stories based on the premise of said machine.
Problem is, I just got around to reading the site today. Early submission deadline is March 31st. That's not long from here. But I'm going to try.