Originally Posted by hailstorm

You can spend half a day just wandering around the tunnels spanning out from Tokyo Station.

If you've never had shabushabu/sukiyaki, there's a good place within the Yaechika complex (accessible from the Tokyo Station Yaesu Underground Central exit) called Tajimaya. Lunch starts at 900 yen with a plate of meat and all you can eat vegetables, and for a few hundred yen more you can get all you can eat meat as well.

Also within the Yaechika complex is a branch of the New York Tribecca restaurant Bubby's, which has the second best American cooking I've had in Japan (the first being the New York Grill in the Park Hyatt)