Not sure it's a front-end (looks like it's a Perforce front-end to Git), but I believe it's an interface that makes the two work together: http://www.perforce.com/git-fusion
In case people are wondering what the Perforce front-end/interface to Git was, I believe it's their "Perforce Git Fusion" product: http://www.perforce.com/git-fusion
Webinar's next week, and I may sign up to see what this is all about. (Disclaimer: Certified Perforce Admin here, and no, I don't work for Perforce.)
Good luck! I'm trying the same thing myself with http://yata.ca. It's more of a party game played with the iOS device, and thought the interactivity with people in the same room would add to the fun. Hope all's well with the second one!