A Marble Computer
Here's a bit of fun for a Friday. Computers add in binary and this video shows how they do it using marbles and wood. If you've ever wondered how your PC does sums, this is a nice illustration.
The creators website is also highly recommended. Now I know what I'm doing on the next Hack-day.

~RS~q~RS~~RS~z~RS~48~RS~)
Its look like a music instrument of ancient time. -) I would love to use MS touch screen table.