Sunday noon stroll in Ikebukuro is always colorful.
The camera-man is the No Eiga Dorobo character, a character from Japan's anti-IP theft campaign. (thanks Gen Kanai) https://www.youtube.com/watch?v=wh89hJlzY5o
One fun adventure in Japan is to visit a Matsuri – local festivals usually around a shrine. Chances are that wherever you are staying, perhaps a couple of stations away, a Matsuri is happening. They usually run for a night to couple of nights. There is lot of local food and some fun games. The best way to find a local Matsuri in Tokyo is to look up the web http://www.gotokyo.org/eventlist/en/list
You can walk past the stalls and just point at the food you want to eat. Snacks usually cost 100 JPY for a stick of grilled meat to 500 JPY for a pack of Yaki Soba. Drink cost around 100 JPY for soft drink to 200 JPY for beer.
As someone who practically lives out of the bag, it is important to get a good bag. There is this company in Japan that makes sturdy canvas bags. I like them for their utilitarian feel and classic looks. They are a bit pricy at about 300 USD but they last a long time and handle all the rough you throw at them. Here is the manufacturer’s web (Japanese only). http://gyuya.co.jp/hinomoto/collection.html