Tokyo is known for its huge variety of history, art and oddball museums. At the top of the heap comes the Edo-Tokyo Museum in Ryogoku, the Meguro Parasitological Museum, Miraikan in Odaiba, the Museum of Contemporary Art Tokyo in Koto-ku, Hara Museum of Contemporary Art in Shinagawa and the National Art Center in Pongi.
Some others I have yet to visit are Yushukan (war museum inside Yasukuni Shrine), the Tobacco and Salt Museum in Shibuya, the Tokyo Subway Museum in Kasai, the Tokyo Metropolitan Police Museum in Kyobashi and the Tokyo Waterworks Historical Museum near (where else?) Suidobashi station.
Here is a useful but incomplete list of museums in Tokyo.
One GLARING omission is Nippon Copack's Hanger Museum in Asakusabashi.
Traditionalists may be slightly wary to call this a museum, in fact.
The modus operandi is pretty clear. On top of presenting the insatiably curious public with a comprehensive understanding of the history and many uses of hangers, Nippon Copack Inc. is a company sells hangers and other furnishings for retail stores. This location just happens to be their headquarters. For one, you can only enter the product showroom, whoops, excuse me "hanger museum" from 10 a.m. to 4 p.m. Monday to Friday. That makes it a bit inconvenient to visit unless your job somehow involves purchasing hangers. Secondly, you need a reservation to get in, so it is not meant for the general public. Also, according to this virtual floor layout map, the area for business meetings is located in the midst of the hanger extravaganza. And you thought museums were only for looking... This one lets you not only browse, but also purchase the items on display!
I guess my favorite thing about the hanger museum is its great selection of hangers. There are hangers of practically every shape, size, color and material you could possibly imagine. I never realized what a diverse range of hangers existed. Truly a must see for hanger buffs. Just make sure you have time between 10-4 on a weekday and a budget for your hanger needs. Oh, and you will probably also want to finely hone your Japanese (or Chinese.. they do have a section called "Shanghai market") negotiation skills for when it comes down to placing your next order of hangers. Happy hanger haggling!