1. A quantum mechanics inspired restaurant
    Being an indeterministic (go easy on me for this one, you know what i mean) reataurant can be fun.
  2. Get a clothing store and replace all dolls by real people getting paid for standing still the whole day.
    The other staff would act as if they were just regular dolls, even act suprised if customers talk about it, like the customer is saying something crazy.
  3. Get some box which looks like a smartphone, so you cannot see through from the back, but it has glass in the front, and then put an ant farm inside. So people will be able to look at their ants while on the bus or wherever they like.