$1000 Bill Exchange
For this game you need to make your own money on your computer (be sure it's clearly phony or it might be a federal offense). Give each person 10 of the bills. They are to try to win as many as possible from their peers by challenging them one on one doing one of three things:
Rock, paper, scissors
Flipping a coin
You must accept any challenge
Sudden death, no two out of three
Challenger has to have a coin and is "heads" on the coin toss.