I was recently exposed to this nifty little advancement in the world of wind-up toys -- the Fridge Rover Zero Gravity Magnetic Wind-up Toy. This little wind-up car is like most others except that it has two small magnets mounted on either side of it, just above its base. These magnets allow the car to perform a minor miracle: it can drive on vertical metal surfaces such as your refrigerator door. I also put the Fridge Rover on my stove door and opened it such that the car was upside down. It still worked!
Here's where you can order your own Fridge Rover Zero Gravity Magnetic Wind-up Toy
If you like the idea and are feeling much more ambitious, here is an instructable on how to make an autonomous magnetic robots that traverse vertical surfaces:
[ Thanks Julia
Labels: automomous, DIY, electronics, robots, spring powered, vehicles, wind up