I recently came across Gource. It allows you to visualize the progression of software development on a git (et al) repository. I ran it over the ardupilot-mega git repo. Its very cool, and a real eye-opener for someone unfamiliar with how much work has gone into the codebase. Its also very cool to watch for someone who has been an active developer.
We ran this on a repo at my work, for a software engineer, its like watching your professional life flash before your eyes.
Someone (I'd don't have the time or much familiarity with the mega codebase) should do a capture of the ardupilot repo gource visualisation and post it as a blog on the main page for all to see.