Gym-Pact is a new iPhone app that rewards and penalizes its users according to their gym membership.
Users create a "pact" with the service, defining their desired weekly attendance they hope to achieve. The differentiating factor between any other service is that these pacts are backed by your own cash. Each time you miss one of your goals, some of your earned cash is redistributed to other users. Each time you meet your goals, you're rewarded.
Miss a day? Fined. Frequent the gym and surpass your goals? Rewarded.
Although Gym-Pact is an unquestionably novel idea, it's not anything I'd personally sign up for. Incentives are all well and good, but paying strangers if I have a meeting that runs too long? Not something I'm a fan of.