I haven’t really done any drunk coding since university (which btw happened waay before git or Arduino saw the light of day gitdown seems just too fun not to try out!), but
Gitdown uses a BreathShield for Arduino and a Ruby script git hook for checking your BAC before it allows you to commit (or not). In normal mode you won’t be allowed to commit if your BAC is above 0.05% but where it gets interesting is when you set gitdown to either krunk mode or Ball(m)er mode. In krunk mode you’ll need a BAC level above 0.05% and in Ball(m)er mode you’ll need to land a BAC between 0.13% and 0.15%.
In the Ball(m)er and krunk modes gitdown also will mess with your commit message as well as post your achievement to the gitdown blog on tumblr.