A giant floor-to-ceiling power meter just went live at the Berkeley Free Speech Movement Cafe. It senses power input from various appliances in the cafe, and displays a live color-coded stacked bar of power usage. A computer receives sensor data, processes it with Python, and sends the data to an Arduino as well as a live monitoring website. The Arduino controls a stack of 93 ShiftBrite RGB LEDs.
More information and video: Berkeley FSM Cafe ShiftBrite Power Meter