This is probably one of the most simple game concepts to add to your round you could think of. Basically, at the end of the round, you don't want to be the last person holding the snake. The only way to get the snake is to three-putt. The snake is given to the first player to three-putt and then is passed along for every subsequent three-putt.

There are alternate variations of this game where you do a partition style snake where there's bets around front nine, back nine, and most holes possessed.