Winter Trip to Japan

A group of friends and I will be visiting Japan in the Winter period, however, none of us have visited Japan before and are in need of some assistance.

We aim to Spend 10-12 days in the country, depending on planning and activities. I would very much like to Visit Tokyo, so could someone recommend activities In and around Tokyo for the Winter Period. We are all in good health so physical activities are welcomed, however as a group we want to spend some time looking into Japanese culture, visiting some temple's in particular.

There will 'minors'(Below 18) on the trip, therefore suggestions must be suitable for that sort of age.

Thank you.

~ Ben

Annual events in Tokyo :
http://www.tcvb.or.jp/en/index_en.htm

It's nice to soak yourself into onsen (hot spa) in winter.

When you say " Japanese culture" ... I think you will find it everywhere, but the one place thats best for culture is Kyoto.

Tokyo has plenty of modern things of Japan, nd cultural things, but Kyoto has the best and most temples and Palaces. Kyoto has 5 full days worth of temples Zen Gardens, and Royal Palaces, in fact theres more history in Kyoto than in the rest of Japan.

Go to Tokyo for 6 days and Kyoto for 6 days.

When in Kyoto, You can take a day trip to Nara ( Largest buudha in Japan. more history etc,) , and you can also take a day trip to Osaka ( 20 minutes away by train.

If you're in Japan for 12 days, get a 1 week Rail Pass that starts on day 6 in Tokyo and lasts until day 12. That way you can take day trips while in Kyoto ( Hiroshima, Nara, Himeji etc. ) and also take the Shinkansen back to Tokyo.

You might be able to fly home from KIX Airport in Osaka. That will save you time and effort backtracking to Tokyo.
It's only 1 hour from Kyoto by JR airport express train.

As much as I love Tokyo, you need to visit more places than just there to see lots of culture and temples.

From the legal perspective, this is the most historically significant archtecture in Tokyo.
http://www.xs4all.nl/~daikoku/junrei/reijo/bangai-6.htm

As Sh says, I strongly advise you to check World Heritage Sites in Japan. These designation is considered to be fairly appropriate.
http://www.jnto.go.jp/eng/location/interests/index_th_03.html