Fitsby is an app that motivates you to go to the gym. Challenge your friends and compete with them in a game of gym check-ins. Bet money or play for fun. The top gym goers of a game are the winners and split the money from their friends who didn't work out as much as they did. Fitsby uses your smartphone's GPS to verify that you are at a gym and also requires that you work out a minimum of 30 minutes before you can successfully check out.