Gitea - A painless self-hosted Git service
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Bonobo Git Server - Set up your own self hosted git server on IIS for Windows.
GitBucket - GitBucket is the easily installable open-source GitHub clone written with Scala.
GitList - GitList allows you to browse repositories using your favorite browser, viewing files under...
GitPrep - GitPrep is a Github clone.