6 days Tokyo with 3 teenage boys

Hi! It's been 6 yrs since our boys last went to Tokyo. We'll be visiting from 14 to 21 June and would like to get some suggestions on where we may bring them this time.

So far, they're keen to go Akihabara to check out gadgets and Harajuku to see the cosplay scene. Any ideas where and what else they may do? Seems 6 full days in Tokyo is quite a lot of time there. Perhaps there's a nice town not too far off Tokyo to make a day trip?

Try bringing them to Odaiba to see a 1:1 scale of a Gundam. :)

[Odaiba]

Gundam front Tokyo
Last summer Guillermo del Toro who directed the movie "Pacific Rim" came to Gundam front Tokyo@Odaiba.
https://www.youtube.com/watch?v=mZusWEAvHUU

Real size Gundam@Odaiba
https://www.youtube.com/watch?v=xldNT5SuVjY

http://gundamfront-tokyo.com/en/

Odaiba map & recommendation rout
http://www.gotokyo.org/en/tourists/areas/areamap/odaiba.html

[Harajuku]

Many celebrities like to visit Kiddyland. For example, Brad pitt, Jonny Depp, Hugh Grant. Steven Tylar deops by there, everytime he comes to Japan.

Kiddyland
http://www.kiddyland.co.jp/

https://www.youtube.com/watch?v=HIv2A0RbVyI

[ Hakone ]

It takes one and a half hours from Shinjuku station to Hakone yumoto station by Romancecar(Limite express). As all seats are reserved, you can enjoy the view from the window and a lunch box. You can get delicious a lunch box at Odakyu department store being very closed to Shinjuku station.

If you go to Hakone when it is sunny day, you see Mt. Fuji clearly.

http://www.odakyu.jp/english/index.html

http://www.odakyu.jp/romancecar/line_up/

Any ideas where and what else they may do?

That depends on their interests and preferences.
(Where and what did they do the last time?)
What I thought of within a minute are Fujiko F Fujio Museum in Kawasaki and Ghibli Museum in Mitaka; both museums require reservation.

We'll be visiting from 14 to 21 June

In Kanto Region it will highly likely be already in a rainy season. Please get ready for rainfall and moist weathers.
http://www.japan-guide.com/e/e2277.html

How about the Railway Musuem in Saitama?

http://www.japan-guide.com/e/e6527.html

Kamakura and Enoshima are pretty cool. Enoshima has got caves and views and a lighthouse and it is pretty amazing walking across the bridge with the hawks milling around. There are some caves in kamakura too, though I didn't get to them because in the end Enoshima took up most of our time.