Enjoy all kinds of Japanese street performers, especially check out the rock dancers. Their fashion is so great. You can see what the one aspect of 70's in Japan. There are many musicians who might become next rock stars in Japan. At the free market, you can also enjoy eating various kinds of asian food.
What is now Yoyogi Park was the site of the first successful powered aircraft flight in Japan, on December 19, 1910, by Captain Yoshitoshi Tokugawa, following which it became an army parade ground. During the postwar occupation, it was the site of the Washington Heights residence for U.S. officers. It later was selected as the site for the 1964 Summer Olympics, and the distinctive Olympic buildings designed by Kenzo Tange are still nearby. In 1967, it was made into a city park.
Today, the park is a popular hangout, especially on Sundays, when it is used as a gathering place for people to play music, practice martial arts, etc. The park has a bike path, and bicycle rentals are available. As a consequence of Japan's long recession, there are several large, but quiet and orderly, homeless camps around the park's periphery.
Recently, Tokyo Governor Shintaro Ishihara announced plans to build a stadium -- with room for 100,000 -- in Yoyogi Park in order to host the 2016 Summer Olympics.
Yoyogi Park has a fenced dog run, one of the few areas in Tokyo where dogs are allowed to be off leash. The dog run is located towards the western side of the park, inside the bicycle path, east of the parking lot at the western edge of the park. The dog run's ground is covered in wood chips, and the run is divided into two sections and contains a few benches. (wikipedia)