I took the Tokyo Water Bus from Asakusa. A ¥1580 boat ride down the Sumida river to Odaiba; an artificial island. The journey took about forty minutes, and, because of the heavy rain, I couldn't really enjoy the views as much as I had liked. In fact, due to the design of the Tokyo Water Bus, the windows are extremely difficult to see from. I imagine on a clear day the Tokyo Water Bus is an enjoyable ride, but in bad weather, I wouldn't recommend it.