I see no one has posted about Fuji-Q Highland, so I will. It's a coaster-type park with the kind of rides that take up too much real estate to be in Tokyo. If it's a clear day (not so common) there are decent views of Mt. Fuji. It makes a decent day trip from Tokyo.

There are SEGA Joyopolis and other types of arcades all over Japan. Particularly amazing are the huge multiplayer games, some clearly with tens of thousands of moving parts. These machines are generally found on the upper floors, so don't let yourself be limited when you just see the "New UFO Catchers" on the ground floor.

You will want to spend time wandering the back streets of Akihabara. Maybe even try a maid cafe, some of them want foreign visitors. Possibly take in an AKB48 show, although that has to be booked in advance online (there is an English website).

And of course, not too far from your hotel on the other side of the station, there is always the "Robot Restaurant."

http://www.flyertalk.com/forum/showt...ferrerid=14479

Enjoy!