Walking around in Tokyo Downtown:

Sep. 26 10:00-18:00?
(You can quit anytime you want.)

Expected Costs: 
Entrance Fee (Edo-Tokyo Musium) 600 Yen (~6USD)
Transportation Cost: 590 Yen in Total (~6USD)

09:45 Join at the entrance of GRIPS

Move to Ryogoku:
Roppongi-(Toei Subway Line)-Ryogoku <<260Yen>>

10:45 Ryogoku

+ Yokoami-Cho Park <<Free>>
   Memorial Hall & Memorial Musium of Tokyo Metropolitan Government for the 1923 Great Kanto Earthquake Disaster
http://en.wikipedia.org/wiki/Yokoamicho_Park
http://www.lonelyplanet.com/japan/tokyo/sights/museum/kanto-earthquake-memorial

+ Edo-Tokyo Musium <<600Yen>>
http://www.edo-tokyo-museum.or.jp/english/

<<Lunch>>

Move to Tokyo Soramachi (Tokyo Sky Tree) by Shuttle-bus <<100Yen>>

+ Tokyo SoraMachi (Tokyo Sky Tree)
http://www.tokyo-solamachi.jp/english/
Shuttle Bus from Tokyo Sky Tree to JR Tokyo Station 

The nearest station Oshiage has a direct access to Narita International Airport by "Narita Sky Access Express".

Return to Nogizaka:
Oshiage-(Tokyo Metro Hanzomon Line)-Otemachi
Otemachi-(Tokyo Metro Chiyoda Line)-Nogizaka <<230Yen>>