"Michigan bar mints its own currency", Day to Day on NPR, 7/5/07:

The owners of the Meanwhile Bar in Grand Rapids, Mich., have created a currency to help raise money for the bar's opening later this summer. For $10, you get $12 in Meanwhile Money. The system is entirely legal, and it isn't new: Historians say local currencies date back to the 1800s.

It's novel, it's cute but ya know, it adds a layer of abstraction intended, I think, to obfuscate patrons.