From the "habit-building by redistribution of wealth" department, Gym-Pact asks you to set the stakes when you sign up and tell the service how much money you're willing to lose if you miss your workouts, and how frequently you want to go to the gym. The service then uses your phone's GPS to make sure you're actually at the gym and not on your couch at home. If you miss too many days, the service penalizes you by charging you the amount you put on the line. The money it collects from people who don't go to the gym is distributed every week among the people who did go, meaning you're rewarded with cash if you actually work out.
Gym-Pact supports more than 40,000 gyms and fitness centers around the country, and even lets you add more - as long as it's an actual fitness center. No home gyms or office gyms allowed, likely because Gym-Pact worries that would make it too easy to game the system. Signing up may be a bit masochistic, but if you really need motivation to hit the gym, this service will give it to you.
- Alan Henry, Lifehacker.com