It's a similar concept that Tim Ferriss talked about in 4 Hour Chef. You'd (with a friend for accountability) put money in an escrow account for an organization you absolutely despise (political, religious, etc). If you fail on keeping your promise (in this case going to the gym) the money would be released. I think he calls it the Stickk method (there is even a site dedicated to it: http://www.stickk.com/)