Sorry, I mentioned in my initial submission that it was for this last weekend's Foursqaure hackathon but I guess it does not show the initial text if you include a link.
So, yeah... you have to have an account to use it. In another comment, I included a link to a simple video we made to explain how it works.
Here's a link to a youtube video that explains what the app does for those who don't want to login: http://www.youtube.com/watch?v=GyCnazRbqGY
Built by Brian Fountain, Justin Isaf, Christopher Kennedy and Harlie Levine.