Steve posted an entry on his blog called Two Pomodoros containing a non-narrated video of him working on the RubyGems project. (For those unfamiliar with the Pomodoro Technique, as I am, two Pomodoros = 50 minutes.)
Why record almost an hour of editing with vim and running tests? Steve explains his own reasoning for doing this in the post. Go read it; it's brief.
Perhaps a better question is, why watch someone editing and running tests? When it comes to open source, I'm a newbie. I suppose I expected to catch a glimpse of hyper-efficient workflow, the super-secret sauce of the Ruby Hero. Which is exactly what Steve tells us not to expect.
What we see instead is someone methodically improving a piece of software, one edit at a time, complete with the occasional fumbling that makes me feel like a blockhead when I do it myself. Only he's doing it in public, where other people can offer criticism, hopefully constructive. Gutsy, and pretty cool.