ohloh.net is a social networking site built around open source projects. People give kudos to each other, and there's some sort of ranking system such that I'm #277 of 29,000 users, which shows that their ranking system is fueled by psychedelics.
ohloh has some cool analyses for the projects, since they analyze the public source repositories of the projects they track. For instance, here's the codebase size for Parrot
There are also great tools to look at who's committed to projects. Take a look at the list of committers to the Parrot project. This is a great use of sparklines to reveal the history of the project through the amount of code committed to the project.
See how Leopold Tösch works like crazy for years on Parrot, then disappears.
My Parrot contributions started out modest, and then I lost interest for a year, then came back a year later.
Compare that to my Perl 5 contributions which are more sporadic, but over a longer period of time.
I've never seen analyses like these done before. If there are others, please let me know in the comments.