PAPERduino

While attending Codebits I came across a very interesting project by Guilherme Martins: PAPERduino.

Considering that the PCB is one of the most "troublesome" aspects of building your own Arduino - unless you opt to buy a ready-to-assemble kit - Guilherme had the excellent idea: why not bypass the PCB completely and use paper and cardboard instead?

The PAPERduino thus becomes one of the easiest and cheapest methods to build your own Arduino.

Considering you'll soon be able to print electronic components on paper using nanotube ink I don't think it's too far-fetched to think of a time when you'll be able to print all your electronics in a similar way.