What do you think is the ultimate hardware hack project?

I had this idea: Take a small portable B&W TV and turn it into a XY vector monitor controlled by arduino. Then add a soundchip from a cheapy casio keyboard (which only reads keystrokes from the patch buttons) Use a calculator for the control buttons. There you have it: the Hacktraxio. (derived from vectrex, hack, casio and axe )

Now you guys!
(I might steal some of your ideas, so tell me if your cool with that or not.)