Check out serenity_rating for some Firefly stamping action. Not my community, but promotion is fun, so eh.
What's a stamping community? You fill out an app, people vote on what character you most resemble. (And, hopefully, you do some voting, as well.) More or less like a quiz, hurrah. (And sorry if that's not enough of an explanation; brain is on the fritz just now.)
So. You know you want to join the party. <.<