Plug in your headphones and glitch out, or jack into an amp and play it as an instrument.
These kits come with a custom-printed circuit board, a noise generating microchip from their live performances, two buttons for modulating the sound, headphone jack and battery. For the adventurous, the noise toys can be reprogrammed to create your own digital instruments (free online sample code gets you started).
Required skill: elementary-level soldering.
The kit is $19.95.