The Open Source community's tools for collaboration have evolved rapidly over the last decade.  From the first release of network-transparent CVS to the public in 1995, to the kick-off of the Subversion project in 2000, to the new wave of distributed version control systems like Git, Mercurial and Darcs, this class of tools has been essential to the success of the Free software movement. This talk will cover the history of these tools, including their algorithms, their models, and anecdotes about their development.