Imagine flashy plasma screens sitting in store fronts in malls or in busy downtown shopping districts with games attracting passers-by to stop and interact with the store. If you win, you get something cool. If you don't win, you still had fun playing.
For an exmaple, please try this (obviously unofficial) "Old Navy Slider Game" that could be displayed in one of their windows. The game is controlled completely with your phone. (Javascript must be enabled)
* This demo is in no way affiliated with Old Navy. They just seemed like a good example. Please don't sue me.