1. Have a swinging robot with 4 arms that can swing on the ceiling using magnets, so it can swing like Tarzan. 

2. A rectangular frame on the ceiling that allows a "spider" to move on 2 axis and then using a string it drops the spider and it picks something up with a magnet. It is inspired by the bungee zombie in plants vs zombie

3. A 3 piece robot, 3 rectangular prisms, 2 with electromagnets and props, to spin and move, and 1 part as the control center. It will move on a magnetic surface.