You flip a coin and the person next to you has to guess whether it is heads or tails. If they guess it right then they flip it for the next person. If they get it wrong then you spin the coin on the table and they have to drink for the time that the coin spins. You smack it down on the the table and then ask them heads or tails. If they guess wrong spin it again and again and again till they get it right. Sounds fun doesn't it.