A few people I work with at MadGlory went to the Startup Weekend in Saratoga, NY and treated it more like a hackathon, to build an idea we'd been thinking about.
Now Play Us is a scheduling app for video gamers. http://www.nowplay.us
We're video gamers and had been having a hard time scheduling games with our friends, so came up with the idea of scheduling games with a simple app. The app is built with Rails, uses Postgres and Redis and hosted on Heroku.
Would love to get your feedback on the idea and the execution.