Tokyo's Shibuya train has a special installation for Christmas that uses its pedestrians' footsteps to generate electricity. A mat using piezoelectric gadgetry runs a LED display board and a small holiday lights display.
The roughly 225 square cm mat near the Hachiko dog statue at Shibuya station generates roughly 0.5W every time someone weighing 60kg steps on it. The amount of foot power it's already harvested is displayed on an LED wall.
Strangely, the installation will only be there until the 25th. I guess the Japanese are really good with taking their holiday lights down as soon as Christmas is over? [Digital World Tokyo]