This is the Portable Tap Dispenser, a backpack with a dispensing tap for your brew of choice.
The Portable Tap Dispenser also has a cupholder so you can more fully cement your reputation as the Beer God of the Party. We're not sure exactly what the bag's capacity is, but it looks plenty big enough to get you a cheer when you walk into a get-together, provided you can serve the beer before it gets flat. It's available now for about $35. [Fun Ideas via Crunchgear]