I haven't played a stringed instrument for half a decade, but something as magical as this could bring me back. See, hacker (and admitted non-musician) [magnetovore] crafted a cello that plays music with invisible magnetism instead of a traditional bow.
And he didn't just load samples onto the thing either. His magneto-cello produces sound with the help of a magnetic bow and four ribbon sensors that serve as string. When he waves the bow across the instrument in classical fashion, the strings send signals to a magnetic coil in the body to make that familiar music. I'm trying very hard not to draw X-men comparisons here.
[magnetovore] was even granted a provisional patent for his project. Which is really impressive. And this is still in the early stages of development. I'd love to see this in a concert hall one day. [Magnetovore via DVICE]