I walked over to the Inner Harbor at lunch, to find some good food and some quiet. I ate at Phillips, in what was essentially a food court. After I finished, and was walking back through the mall area, I saw a young mother and her daughter, perhaps two years old, jumping around on the floor. As I eased over, I realized that there was a projector mounted on the ceiling, directly above them, projecting a game court on the floor. There was a digital ball (of sorts) bouncing off of the projected walls, and the two were trying to step on the ball the change its course to the opposing goal.
It was one of those times when you just seen, for the first time, something that you suspect will be huge in the future.