If you have enough time and curiosity, also stamina to keep yourself awake all night long on Friday, you can enjoy Tuna auction at Tsukiji Fish Market.
Every Saturday early morning around 5pm, limited numbers of atendees for only 2 tours can join. I think you may need to queue, in my case with my friend, I got queuing for 2 hours to obtain our seats. But this tour is worth joining. Auction master yells its price very particularly, you can see powerful, traditional trading scene in front of you with frozen tuna.
Here’s official guidance in English.
And this is picture that I took last time I went.
Wouldn’t it be exciting?