Git
Git is a member of Software Freedom Conservancy, which handles legal and financial needs for the project. Conservancy is currently raising funds to continue their mission. Consider becoming a supporter!
Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
Git is easy to learn and has a tiny footprint with lightning fast performance. It outclasses SCM tools like Subversion, CVS, Perforce, and ClearCase with features like cheap local branching, convenient staging areas, and multiple workflows.