Despite our best attempts at trashing the planet in hopes that Al Gore will grow a beard again, we can't help but love repurposed electronics. The Plink Jet, spotted at NYU's ITP Winter Show
2007, uses the back-and-forth mechanisms out of four old ink jets to slide up and down four guitar strings, with various knob-controlled settings to control pitch and strumming patterns. The resulting noise is nice hybrid of robotic clicking and analog twang, but we hear HP charges a fortune for the strings.
Plink Jet makes beautiful music with dried up ink jets