See two years of source code development in a 6 minute visualization. Tayken used a script to visualize code development in the Dangerous Prototypes SVN repository at Google Code.
Watch for the 2 big reorganizations, one in 2010 and again in 2011. In the beginning there’s a single long-term contributor, but around 2010 the number of long-term contributors explodes.
Youtube’s codec made the first 4 seconds a little fuzzy, but it’s ok after that.