Harry Beck’s original London tube map was inspired by circuit diagrams, so it’s only fitting that TrainTrackr’s tracking maps showing the real-time positions of trains on the London Underground and Boston MBTA are literally circuit boards, using LEDs to indicate train positions. (They also have an LED map showing rainfall data in the British Isles.) Prices range from £99 to £249 (US$149 to $315). [Mapping London]