GymPact | Never miss another workout.
gym-pact.com
gym-pact.com
In their FAQ:
> The minimum bet is 5$ and the minimum reward is 0.5$
> Our users make it on average to 90% of the days they commit
I was toying with a similar startup idea but for losing weight. (I haven't figured out how to verify users' weights though, gympact has the advantage they can use GPS to verify you're at the gym.)