Awesome slice of nature in the middle of the concrete jungle. The weekends can be quite crowded with expats and Japanese having picnics and playing around. Very tranquil during the week, a great place to stroll if you need a quick break from the city.
CoCo's in my opinion is some of the best Japanese Curry you can get in Tokyo, the flavor is amazing. Being able to choose how spicy you want it to be is another bonus. A great place to go for some quick, but quality grub.