Tepco Electric Energy Museum

Called Denryokukan, the Tepco Electric Energy Museum is the building on Jingū-dōri with the R2D2-shaped silver dome - it's clearly visible from the Hachikō statue. Operated by the Tokyo Electric Power Company, it offers seven floors of knowledge about electricity production and consumption; if you're not fortunate enough to be invited to a Japanese home, the 4th-floor collection will give you a good idea of the state of the art. There are lots of hands-on exhibits, normally a hit with kids.

Signage is almost entirely in Japanese, but there's an excellent English handout on each floor.