Static Void Games
This is the open-source project behind Static Void Games. This GitHub repository contains all of the code that runs on the server, packaged in a way that makes it possible to run it locally. Users are encouraged to clone the project, make changes, and create a pull request to submit those changes to the live site.
Static Void Games is a website devoted to teaching people how to program through open-source games and applications, as well as tutorials, and this repository is an extension of that goal. Static Void Games also acts as a free webhost for indie game developers.
However, this code could be used as the base to pretty much any kind of site. I just ask that any projects you base off of Static Void Games code be released as open-source as well (and not doing so is a violation of the GPLv3 license it's released under).
To get involved, check out the wiki for instructions on how to run the code and submit changes!