More of the Amazing Circuit Scribe.
With a little know how you could make some relatively complex circuit boards, you could conceivably draw a very basic computer on a piece of paper (obviously adding a few things). I've seen people make entire computers in Minecraft using redstone which is conceptually the same thing as this. I could definitely see this as a very useful teaching aid.
I was going to say conductive silver ink pens have been around for ages, used for circuit board repairs, but looking at the kickstarter page it seems they are marketing this as a teaching tool, as a replacement for breadboarding.
While it may be more cool than using a breadboard, you are drawing with silver, so it's not going to be cheap, and what about disposal/environmental issues? If this were to be used where I work all the paper would have to go into hazardous waste disposal, adding even more to the cost.