Pi in the Sky

Here's the ideas (nothing original, for me, it's about the evolution):

• Pi Tank.  Preferably autonomous.  Working up to Pi Gaming, human vs AI, nerf guns anyone?  Add the range detector, and see if it can map a room.  
• Camera - time lapse and/or night sky.
• USB Robot Arm - as built from Maplins kit.
• Drones.  Add them with the rangefinder option, and you've got those cool mapping spheres from Prometheus.  Just need the scanning lasers next!