I just gave a talk in Kraków at Railsberry where I announced Hopper, an open source Ruby code analysis project.
Hopper is a Sinatra app designed to pull down tens of thousands of Ruby projects from GitHub, snapshot each repository into ten equidistant revisions, run them through a battery of tests (which we call Probes), and hopefully come up with some deeply moving insights about how we write Ruby.
Codestat is the live version of Hopper. It's available at codestat.us.
Codestat is a bit of a work-in-progress. It's running on an underpowered instance, and I'm pretty sure I might be blowing out the database from time to time as we settle on what makes sense to model all the data.
Hopper is one big experiment. I think where it is today is a long throw away from where it could be tomorrow. I welcome your thoughts, issues, and Pull Requests as we build something nifty together.