Japan Rail: Yamanote Line Tour
(Wikipedia): The Yamanote Line (山手線, Yamanote-sen?) is one of Tokyo's busiest and most important commuter lines. Running as a circle, it connects most of Tokyo's major stations and urban centres including the Ginza area, Shibuya, Shinjuku and Ikebukuro with all but two of its 29 stations connecting with other railway or underground (subway) lines. It is operated by JR East.
Circle the Yamanote Line in under 4 minutes below. I rode on this line a lot when I visited Tokyo.