There’s a great tool available to create impressive visualizations of source code repositories:
“Software projects are displayed by Gource as an animated tree with the root directory of the project at its centre. Directories appear as branches with files as leaves. Developers can be seen working on the tree at the times they contributed to the project.
Currently there is first party support for Git, Mercurial and Bazaar, and third party (using additional steps) for CVS and SVN. “