The invisibility cloak idea is an interesting physics concept that bends light around an object and thus making it effectively 'invisible'. Well known in fiction of course. A new variant of the idea described in Technology Review allows one object to look like another.
It makes the imagination run riot, but none of these ideas are yet practical in any full-scale way. Off the top of my head, you could redesign portions of a retail space without really moving anything. Be patient for this one.