When I first saw Rovio[1] for sale on eBay, one clever eBayer decided to charge $1 to let you use it. Since you could control it remotely through wifi and the camera, you were able to roll around his house.
So then I thought, what about taking this further? Like an arena where you could battle them or something? Better yet, get a warehouse and build rooms, escalators, themed areas like a park or waterfall. Allow people to use their mobile device to log in to their bot, avatar toy, etc and control it. You could do things like teleport to other parts of the warehouse, where you'd just embody a different bot. With augmented reality, you could even sell "stickers" to decorate your bot or battle car, etc. Advertising could be tastefully placed around the areas as an additional revenue stream.
Of course, prox sensors would be a must if the object of the environment isn't to bash everyone to bits.
It's pretty far fetched, but I think it would be fun!