A drink made with hot chocolate mix and coffee--usually prepared in the office kitchen. In an emergency, it's a substitute for an actual mocha when one can't get to a coffee shop.
Erin: "I didn't have time to run to Caribou, so I had to make do with a Ghetto Mocha."
Rick: "Ghetto Mocha, huh? Not as good as the real thing, but it'll do in an emergency, mofo."