TYPO3 Forge runs Redmine
TYPO3 is a free, feature rich and widely used content management system written in PHP.
The TYPO3 team have chosen Redmine for their new Forge:
For the coordination of the TYPO3 5.0 development efforts, we used to run a Trac installation which hosted our issue tracker, code browser and a wiki. But we were really missing some important features (like being able to set up sub projects) and were looking for alternatives. Fortunately, Martin Herr came across a tool called "Redmine" which looked very promising.
So we created a new website - the TYPO3 Forge. Its purpose is to centralize TYPO3's development projects and provide a home for teams who are in need of an issue tracker, code browser and subversion. Although forge.typo3.org currently accommodates only TYPO3 5.0 and FLOW3 related projects, we structured it open enough to be ready for the TYPO3 v4 team and other projects.
Read the full announcement written by Robert Lemke.