CircuitPrinter

There's an Epson inkjet printer that has refillable tanks for ink. They can be filled with some kind of cool material for printing conductive ink. You can print traces on photographic paper.

There's also a pen that can draw circuits on the same paper. You can use your hand to draw with this pen. It's pretty cool from an art perspective.

The bottom right corner of the paper has a battery in the binder clip. The fold is touching the + and - sides of the battery, sending power to the LED, which is fastened with masking tape.