Ketchup is a polyglot version control client (currently supporting SVN, Git and Mercurial).
Clone the project by running git clone git@github.com:mattlangtree/ketchup.git in Terminal.app.
The project Ketchup.xcodeproj can be opened in XCode and you can build the app by pressing the Run button.
No other steps are (currently) needed to compile the app.
The main use case is to drag a folder of any git/svn repository onto the Dock icon of Ketchup to bring up the commit window.