What are some must-do/must-see things in Tokyo?

Miss Wests list pretty much sums it up. But I'd say that everywhere you go is a total trip. Sit back and enjoy the ride. Having a "local" can be a really great idea as the language barrier is pretty thick. They have volunteer guides if you contact the JNTO. I like Shinjuku and seedy Kabuki-cho at night. The tiny bars of Golden Gai are little treasures. Roppongi for me has lost its magic, though. I prefer Shibuya or Aoyama. A lot of kooky joints there! Shibuya at night will knock your boots off. Careful or you may end up partying all night. You like gadgets and electronics? Check out Akihabara or "Electric City". The multi floor Llaox will blow your mind. Go at night for the light parade that puts Vegas to shame. If you can find out about a Matsuri or "street party" then go to that. Drink cold beer and dance in the streets with the locals. You may have to take a train to the burbs but it'll be fun. Make the smallest effort and you will be welcomed with open arms. Take the Chuo Line to Kichijoji and then stroll around the park. After eat at the Izakaya at the edge of the park. Drink huge cold beers and eat chicken on a stick. That would be my top recommendation. Yeah. Kichijoji is really cool with lots of shops, restaurants and young folks. It's outside of Shinjuku about 25 minutes. Way cool.... Only 3 days? Just tool around and take it all in. Just sitting in one place sipping coffee and people watching is fun enough.

Tokyo profile including history, geography and administrative regions, economy, and demographics. Also includes sections on transportation, education, and tourism. en.wikipedia.org/wiki/Tokyo This site might help you.

go to the tokyo metropolitan building - on a good day you can see for miles and miles. also go to tokyo disneyland, but only if it's a school day or the place will be packed. also, you might like to check out the Sony building (i'm pretty sure that's in tokyo) hope that helps and enjoy your time in tokyo p.s. if you're really adventurous, try a peak-hour subway train, that's always "fun" :)

I would recommend the Imperial Palace, the Ginza and Tokyo Tower. If you would like to spend a day, go to Mt. Fuji. It's about 2 hours from Tokyo on the local train. Take the JR Chuo mainline from Shinjuku Station to Kawaguchi-cho Station. From there you can take a bus to the 5th station on Mt. Fuji. and from there you can take some awesome photos and enjoy the view! A lot of people that hike to the summit start in the late afternoon, spend the night near the summit and then wake early to arrive at the summit to view the sunrise. July and August are the months for climbing. I know that you only have three days, but I just thought I'd throw that out there. Enjoy your trip.

Tokyo tower Ropponggi hill The king's residence

Shinjuku, Shibuya, and Roppongi are famous for a nightlife. Roppongi is where a lot of foriegners go and hang out. Emperor's Palace is cool. Tokyo Tower. Meiji Shrine and Park. Ueno is a fun area and they have a cool zoo. Go see Tokyo bay. Have fun! I'll actually be there next week for part of my Obon vacation. I am getting excited.

Tokyo DOME

Oh you are going to visit Tokyo? Umm, to be really honest, Tokyo doesn't have lots of great places too see, for it is just a large city with tall buildings and crowded people and you may feel bad. You can't see the reality of Japan and Japanese people, perhaps. I can recommend some famous places among visitors, but they are not very good; Tokyo tower, Koukyo(皇居, where the Emperor lives), Asakusa(浅草) and stuff. If you could go further, out of Tokyo, you should definitely pay a visit to Nikko-tou syou guu(日光東照宮) in Tochigi(栃木). You see a very beautiful temple there! All I can say is that Tokyo looks like every other big cities in the world such as New York, London, Paris, Hong-Kong...anyway I do hope you'll enjoy this travel!