The game was new to us, but he was quite a fan. The idea is that when the bill comes, instead of dividing it up everyone drops their credit card into a folded up napkin. The cards are mixed and someone pulls one out at random. The unlucky person whose card is drawn pays for the entire meal; everyone else gets off scot free.
Eat Foo: The economics of credit card roulette

Source: eatfoo.com