dyeSight $2 Multi-Touch Pad
I guess most of the people reading this will have seen some of the multi-touch demos by Jeff Han, Apple and Tactiva. I wanted to play around with some ideas that required a multi-touch pad, but there aren't any devices available (Tactiva aren't shipping...)
Long story short, I made a simple one from a plastic bag, some dye and a camera:
More information coming soon.