These are some interesting adventures for anyone visiting Tokyo (and maybe for some already living here). I deliberately haven't gone into detail so as not to distract from the surprise. Each has it's own little secret which I hope brings you a smile as you find them and think "so that's what he was talking about".
1 Visit Harajuku on a Sunday afternoon and watch the wild and weird costumes go by
2 Take the boat from Hamamatsucho to Asakusa along the Sumida River and drink a cold beer
3 Sit with the forty seven ronin at Sengaku-ji and think
4 Ride the Yamanote line all the way around
5 Walk from Ueno Station to Okachimachi Station on a Saturday afternoon
6 Find Nombe Yokocho in Shibuya and go into any of the little bars
7 Eat at a modern kaitensushi restaurant and video your order arriving
8 Sing you heart out on the stage of Smash Hits! in Hiroo
9 Ask if you can try the paddle at Inakaya
10 Buy flowers for the person you're with
If you found this interesting you may also enjoy Ten things to do in Karuizawa as well as Ten things to do in Osaka. And if you're still looking for things to do in Tokyo, here's the original Ten things to do in Tokyo. I hope you enjoy Japan.