GitLab is a development collaboration tool and git DVCS frontend. It includes repository management features, code reviews, an issue tracker, activity feeds and wikis. GitLab provides fine-grained access control, user management, 5 permission levels and branch constraints, and can utilize LDAP/AD intranet authorization. Powered by Ruby on Rails it comes as open source package, and as commercial supported enterprise version.
Fossil is a distributed version control system, quite robust and easy to use. It manages local and remote repositories, user permissions, has a built-in wiki, bugtracker, release blog and an extendable web interface. It's github-in-a-box as all features are packed into a stand-alone executable which also doubles as server. Internally the database utilizes SQLite and allows extending that or its user interface through TCL or the builtin TH1 scripting language. An optional JSON API permits further
MantisBT is an open source issue tracker that provides a delicate balance between simplicity and power. Users are able to get started in minutes and start managing their projects while collaborating with their teammates and clients effectively.