We use git at
https://bugs.launchpad.net/evergreen and offer access to the "working" Evergreen repository to anyone who sends in an SSH key. We ask that you create "topic branches" based against main for each feature you want to contribute and keep them separated, if you can. Also, please open a bug at bugs.launchpad.net/evergreen and point at your branch when you're ready to have it reviewed. More info on how we use git at
http://evergreen-ils.org/dokuwiki/doku.php?id=dev:git