That's a great idea. I've recently started browsing through some of the top-voted questions and answers at http://codereview.stackexchange.com/ to see how coding / scripting can be improved.

Edit: After browsing through the list of projects, I found three which were both interesting / useful to me and (just about) within my abilities:

* Guido van Rossum’s web-site crawler

* Ned Batchelder’s template engine

* Malini Das’ simple Continuous Integration system