I have been in the community for over a few years know and run my own server at home. I have also written a few contribs, one of them is smeserver-subversion which implements Subversion for SME Server.
More information can be found at http://www.snetram.nl.
SME Contribs development
Since smeserver-yum-1.2.0-41 a new repository is available on SME Server, which holds contribs made by all kinds of people using and benefitting from SME Server. Since development is tracked and source code is stored in CVS, I made my self a CVS Cheat sheet.