It's mostly learnedax's fault, but since he hasn't piped up: it's a very simple game. Start a sentence with "The Amish 18". Finish it. Trade definitions back and forth -- the stranger, the better. It's amazing how long it can keep going when people are in the right mood.

The most popular seed to start with seems to be something along the lines of, "The Amish 18... is the world's fastest and most exciting horse-and-buggy race." It rapidly goes downhill from there...