This article from ZDNet via Smart Mobs talks about how cellophane is a pizoelectric. Pizos are materials that can bend if an electric field is applied to them.
Pizos are important as both sensors and actuators. If you apply an electric field to pizos, they bend, and hence they are actuators. If you bend a pizo, it should generate an electric field.
To make a pizo with cellophane and a thin layer of gold is a pretty shocking development, because they are cheap materials (a thin layer of gold is not too pricey). It opens up the door to lightweight and cheap pizos.
Rollable keyboards are now possible to be cheaper to make, in addition to surface skin tables for user interactive screens. Wouldn't it be possible to use something of the equivalent of Surface Acoustic Waves, to detect where something was touched?