Jeremy Bornstein proposes a party game/Prisoners' Dilemma variant called "I Eat Poo," in which the players pass their phones to their left and invite the player there to type (but not send) an embarrassing message into their own Twitter account. Phones are handed back and each player gets to decide whether to allow the message to be posted, or to forfeit $20 to the message-writer; the phones are handed back to the message-writer, and the hand-over may also include a covert $20 payoff. The climax comes when the final accounting is made: if everyone has paid $20, or no one has paid $20, then nothing happens (the messages aren't posted). Otherwise, the paid-up don't get posted, the unpaid do, and the pot is split among the message-writers.
When you receive a phone from someone else, it should have the phone’s Twitter client active, with whatever UI there is to make a new tweet. Then you enter in anything you want. Anything. There are no rules to this part. However, and this is very important: DO NOT POST yet. You may get to do that later. Instead, hand the phone back to the owner.
When you receive your phone back, look at the proposed tweet. Then hand it back to the same person who composed it.
If you don’t want them to post it, conceal a $20 bill in your hand. If you want to allow them to post it, put nothing in your hand. Making sure to hide anything that may be in your hand, put it forward onto the table. Wait until everyone has put their hand in, and then all of you must open your hands simultaneously.
If everyone has $20 in their hands, the money goes into the pot for the next round and nothing is posted.
If nobody has $20 in their hands, nothing gets posted.
If some people have $20 and some people are empty-handed, posts happen for those people who didn’t pay up, and the money (including anything already in the pot) is distributed evenly to those people who didn’t pay.
Finally, any tweets made during this game may not be erased at least until the NEXT occasion that the person plays the game.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.