Close to the much more busy Roppongi, Akasaka station is full of all kinds of restaurants, shops and hotels. Is a nice place to spend a Sunday doing nothing, eat great food and relax in one of its many parks. Also there are a couple of small shrines that are worth the visit if you like that.
Hikawa shrine is a really old one. Is one of the few shrines that survived the WWII bombing, so what you can see today is been standing there for a while. Each time I go here there is a special atmosphere around the place, a place to visit if you want to forget about the noise and the crowds for a couple of minutes.