3-6-9 Clap
Everyone sits in a circle and in a clockwise direction takes turns saying a number or clapping beginning from number 1. The object of the game is to say the number when it does not include a 3, 6, or 9 and clap otherwise (ie. 1, 2, clap, 4, 5, clap, ...). You must also clap the number of times that a number contains these three digits (ie. 35 is one clap, but 36 is two claps). The game continues until someone messes up the sequence. They are subsequently punished in a humiliating fashion. In the non-alcoholic version of the game, the victim must lie on his back while everyone else beats him for a short period.
To make the game even more difficult, there is a variation where the word "Asa" must be said in place of every number that can be divided by 5.