As a disclaimer, I do remember discussing this game with some friends when I was younger. Since large quantities of beer were involved, I do not remember who came up with the original idea.
Step 1: Your Equipment
1. A putter for each player
2. One golf ball
Depending on the individual needs of the player (and whether or not you wish to remain friends with the other players when you are done), other equipment may be needed, such as:
2. Shin and Elbow Pads
3. Jock Straps
You get the idea.
Step 2: The Rules (or Lack Thereof)
The game is played like this: Each player is given one putter, but the entire group plays with only one ball. One player is chosen to "drive" the ball towards the hole. Whichever player manages to put the ball into the "hole" wins the round.
Other rules may be applied as needed. The choice is yours.
One final note: Most golf courses frown on Full Contact Golf being played on regular courses, so try to be creative about where you play.