This source is for the previous version of http://www.gratefulplace.com. For a walkthrough, check out http://www.flyingmachinestudios.com/programming/dissecting-gratefulplace/
If you want the repo for the current version, have a look at http://github.com/flyingmachine/gratefulplace2.
Copyright © 2012 Daniel Higginbotham
Distributed under the MIT License.