Foursquare held its annual Hackathon over the weekend, and they saw over 200 hackers participate in building apps using Foursquare’s API. Foursquare touts high participation in NYC, San Francisco, and “unofficial” sites like Myrtle Beach, Tokyo, and Los Angeles.

Out of dozens of app submissions, Foursquare has chosen a winner. The Grand Prize goes to Gym Shamer, an app that allows users to set fitness goals and then calls them out, publicly, when they fail to meet them.

Let’s say you set a personal goal of going to the gym three times in a week, If you don’t end up checking-in at the gym three times, Gym Shamer will publish that embarrassing news via your own Twitter and Facebook accounts.

It may look something like this:

Other Grand Prize winners include Reward Board, an app that allows business owners to display real-time check-ins at their stores – including information on the mayor and leaderboards. Those business owners can set up rewards if they want, and even print out receipts for check-ins.

And there are now over a dozen new apps you can connect to your Foursquare account, as they have been given Jury Prize honors from Foursquare. One such app is called FlashSquare, which is like Snapchat (or Facebook’s Poke). It allows users to share photos upon checking-in, but they will only be visible for a few seconds. Another app, DinerBeware, informs users about Health code violations at restaurants at which they check-in.

For a complete look at all the prize winners, head on over to the Foursquare blog.