UPDATE: "Open Atrium has moved from its single monolitic repository to an install profile and a drush make based build system. This is a change that primarily effects developers. The complete, ready to install, download will continue to be offered at http://openatrium.com". Details here. Thanks, Jeff.
I've been playing around with the Open Atrium project (Features rule!), which is a very cool Drupal-based intranet distribution created by those smarty-pants over at Development Seed.
I went to download the latest version, but noticed that (as of December 31) it hadn't been updated with the latest version of Drupal core. Now I usually pull updates from the Drupal community via CVS while keeping whatever project I'm working on in Subversion, so I was looking for a way to do so for Open Atrium.
It turns out that the project repository is hosted at GitHub. Using Git to pull down the latest version of Open Atrium turned out to be pretty easy. Here's how I did it.