We first saw this invention on TED Talks a couple of years ago. It allows you to make 3D objects in your own home. From simple things like keyrings up to technical parts like gears for a machine.
The thing that really got our attention was the fact you only need one piece, and this one piece and replicate itself.
This is a link to RepRap, the OpenSource project behind this whole enterprise
This company is called MakerBot Industries, they make kits