Challange Coins?

It really makes more sense in a military context. First, you've actually "accomplished" something for the right to carry it. And also, its an understood concept that is somewhat easy to enforce. If someone at a bar slapped his down, there's no way I'd buy.

Maybe it has some use among a group of buddies who implement that understood rule. Interesting. I guess I know something cheap to get my cousin for his birthday next week now