Etch a Sketch Laser cutter
I've just completed a project and I wrote the details up on Just Add Sharks. We replaced the brains on one of our Blacknose laser cutters with an arduino to create a Etch a Sketch controlled Laser cutter. Time will tell how many fires we get during operation :)
http://www.justaddsharks.co.uk/arduino-based-etch-a-sketch-laser-cutter/