Companies such as Facebook, Google, and Foursquare regularly host events that give developers the keys to the code and let them carve it up, all in hopes of producing innovative new applications for the platform. At Foursquare's February hackathon, for example, 150 developers mixed and mingled with the company's engineers and got their hands dirty with the API. The results, according to Foursquare's blog: 25 pizza and 300 cups of coffee consumed, 15 hours of coding, and 39 new apps. The winner? The Dealio, who turned a suggestion from a Foursquare forum into an app that enables users to leave private messages for friends when they check in at a venue.