I'm sure Jib would know more specific names than I will, but there is a place called 'palette town' or something similar, with the tokyo big sight I think it's called and a toyota building/exhibition with tons of stuff to see. The fuji building is near there, as well as a neat museum. A statue of liberty, some kind of rocket-like statue, just alot of stuff to see. Lots of walking if you want it, and a pretty interesting day. I went from there to ginza and then walked for several hours bar hopping until everything closed.
I'll be there in December as well and may do a repeat.