If you're in Tokyo this new year, I highly recommend paying a visit to Zojoji temple.
There are loads of people, food stands and a monkey show. It's traditional and lucky to bring in the new year by paying visit to a shrine. The monkey show is a tradition dating back hundreds of years
The show goes on continuously from 9-5pm Jan 1-5 at Zojoji grounds bad is free to watch (but you should donate something when they come around with a collection bowl).
Here's a video I just took:http://www.youtube.com/watch?v=W7pphPHTBfQ