I saw this on the Charmed spot!
The rules are simple. I put a coin in and the next poster tells me what I got, and then puts a coin in.

For example:

Makintosh: Insert coin.
Someone: You get The Tales of Beddle the Bard *Insert coin*.
Someone else: You get to go to Hogwards *Insert coin*.

Get it? Yay!

*Inserts coin*