It isn’t quite attractive to look at, but the stylus from Microsoft Research can be quite a handy piece. Depending on how you hold it, the tool can be whatever you want it to be. The stylus makes use of capacitive multi-touch and orientation sensors to see how it is being held, and executes the corresponding function. Hold it like a pen, and it will work as a pen, hold it like an airbrush, and it will function like one. Hell, you could even play the flute or saxophone through this contraption.