Traintrackr is a light-up circuit-board map of the London Underground or Boston Metro

Traintrackr is a powered circuit board showing a map of the London Underground, lighting up in real time to show train positions on 333 stations on all 12 main lines. It connects to the tube's API for live location data every second. The board is 400mm x 300mm and sells for £249. (There's also the Boston Metro)