If you are in Tokyo in October you should definitely go to Oktoberfest in Odaiba. It is a fantastic festival with what else, that is right beer! Actually they have a lot more than just beer. There are German music groups playing, people dressed in German clothes, and lots of good German Food. It makes for a nice day out and you might even forget that you are inTokyo and think you are in Germany for a moment.
I am an American living in Tokyo and love it! I am the director of The American Guitar Academy which is the premier place in Tokyo to take guitar lessons/classes. http://www.theamericanguitaracademy.com/