A new method of printing solar cells and other circuitry on thin, flexible materials has been developed by Miles Barr, a grad student at MIT. The process, oxidative chemical vapor deposition, uses conjugated polymers, plastics with good conductivity and some semiconductor properties. The plastics are also flexible, stretchable, and even foldable. The dry process works on materials such as Saran wrap, rice paper, even toilet paper. Applications seem endless.
For more info and a video of the material in action, go to: Flex circuits on delicates