Hammerschlagen - a game best played late at night once the beer has done it's job. Although it's quite simple, it contains hours of amusement.

Here are the rules:
1. You'll need:
a. One tree trunk or large piece of wood.
b. A box of 3 inch nails with large heads
c. A sledgehammer with a flat and pointy end
2. The object:
Be the first to get your nail flush into the wood
3. The set up:
a. Each person nails the nail lightly into the stump
b. One turn at a time, each player gets one swing.
c. Play continues until the winner gets their nail flush into the wood.
d. The winner gets a prize (be creative!)

Variations on this game can easily be played. It is highly amusing.