I thought this was pretty cool. A creative father's young son asked him for a remote control car. Instead of going out and buying one he instead decided to use his 3D printer, a battery, and a $4 motor off of Amazon.com to create a battery operated toy car for his son.

He first started by printing 2 gears, one smaller, and one larger. Once done, he used Blender to create the rest of the car's body. They added an extra battery because of some weight issues, and walla! they had their toy. They went through a few iterations before finnaly getting the car just right. It's as simple as you can get, as there is no on/off switch, so you just have to disconnect the battery to turn it off. I thought this was a great way to teach your kids a heck of a lot, while also having fun with them. Check out the pictures below: