Oh My Git! The Game

 Learn how to use Git with this fun, interactive game which takes you from being a complete newbie to efficient expert by covering everything you are likely to need. 

Oh My Git! takes an unusual approach. Instead of being offered as an online playground it ships as multi-platform, self-contained, binaries including git-bash!

I installed the Windows version and despite the cavet that it's still under development and laggy under this OS I didn't notice anything annoying.

full article on i-programmer