This is The Last Barfighter. It's a 2D arcade fighting game. It looks pretty awful, but that's OK. The point here isn't to simply enjoy a video game. It's to beat your opponent so you get beer.
The video above explains it all. Players insert their cups, they fight, and the winner's cup is filled with brew. On the down side, this is a promo piece made by an ad agency for a brewery. On the up side, well, now that the idea is out there, hopefully someone can come up with something a little more widely available.