I'm joining, definitely.

I just started my own similar project: One Month Codebase http://zipwith.blogspot.com/search/label/one%20month%20codeb...

The idea for my project is to focus exclusively on a single codebase to study, experiment with, and contribute to, each month. And write it up in such a way that those who haven't yet gotten the courage to jump in, can try their own hand at contributing to OSS.