This game is based on a dutch game called: 'Stoelendans'...basically this is like musical chairs with alcohol added.
You start with placing some chairs in a circle in the room. If you're playing with 8 people you must place 7 chairs, with 5 you must place 4 chairs...etc. Play music while all the competitors walk around the circle of chairs. Have someone who turns the music off at random moments. As soon as the music stops everybody must take a seat on one of the chairs. The loser (the one who wasn't able to take a seat) must drink a full beer and sit out. The rest drink 1/2 a beer and continue to the next round. You take a chair out of the circle every round.
You can vary the drink amounts for each round if you wish. Happy drinking!