RabbitVCS is a collection of graphical tools providing simple and straightforward access to version control systems from interfaces you already use.
Currently, it offers Subversion and Git integration from Finder, Nautilus and Thunar file managers, and the Gedit text editor. (See the Support Matrix for a detailed breakdown including supported versions and alternatives. Patches supporting other version control systems, file managers and clients are welcome.)
RabbitVCS is primarily inspired by TortoiseSVN. It is free/libre/open-source software written in Python using the PyGObject library (formerly PyGTK).