A drinking game where a bunch of drunk males (females are welcome too, though they rarely choose to participate) stand around in a circle with one unopened can of beer. The first player shakes the can vigorously and then smashes it against his forehead. The can is then passed to the left. The next player shakes it vigorously and again smashes it against his forehead. The game continues in this fashion until the can eventually explodes against the forehead of one lucky guy, thereby making him the winner of the frummel and earning him the respect of his peers.
I cut my head pretty bad in the frummel last night, but it was totally worth it!