Hmmmm ... that name, that number. Does it refer to a particular date in history? Does it mark the number of cups of coffee they serve in the average day? Is it some secret code of some clandestine Austin subculture? Well, not unless your name is Jo. See, the 503 used to be housed a few doors down at ... er ... 503. Same homey vibe and yummy stuff, just in a new house.