Im now trying alot of experiments using AR, or Augmented Reality. Using the Vuforia service, now built into Unity its actually pretty easy to do.
A City, where you can get down on your knees and look around, Ive got location based audio to work, so when you approach a character they talk, and looking to get touch to work so that you can fix stuff. Im thinking of a kind of Groundhog day senario where things happen, and if you can solve them they dissappear, and dont return, but if you dont they loop. So a building catches fire and if you call the Fire Brigade they will come and fix that, if not, the fire burns out, with casualties (Shown by a zealous Hearse drive who turns up after every accident. A Mother who has lost there child, a UFO that abducts a car (you just move the car to thwart the aliens)
Also a kind HSE game (maybe selling at work) a dangerous warehouse where all sorts of accidents happen… same gameplay.. fix them and they clear away.