Ask HN: Game where the participants change the rules?

On HN I once saw some discussion about a game meant to be played via bulletin board or email. Each turn, a participant may change a rule. The game ends when a player wins, but players can also change those win conditions. Surprisingly, some googling doesn't turn up very much, and I figured an HN post would be more valuable anyway. It's amusing to think about trying to get a game going via this HN post. Each comment subtree would become its own strange little game. It'd never work; chaos would ensue. Amusing chaos. Probably best not to do that though. Anyway, does anyone remember this game? What was it called?