Saul Bass capacitive touch light switch
So file this one under "pointless" – but it's still fun!
Using Bare Conductive's conductive paint I created a capacitive touch light switch. Uses an Arduino, a relay and of course a light bulb. Of course it could do more than control a light; it could be an interface to peruse Saul Bass's work, controlling motors and the like. Or something.
You can find out how to make your own on http://bareconductive.com