Izakaya are Japanese style pubs, great places to meet and have drinks. Many izakaya also serve excellent food. Try having a few drinks while you sample some popular izakaya foods.
If you like fish and seafood, you should try one of the Isomaru Suisan 磯丸水産 izakaya. Isomaru is a seafood specialist and has over 50 stores in the Tokyo area. All tables come with a small grill and a toolbox for cooking with skewers, tongues, scissors, sauces, and spices. It is fun to cook together at the table and the staff will help you if you are not sure how to prepare something.
Many people order some clams to start the meal. You can see the different kinds of fresh clams sitting in the water tanks. The staff will bring some to your table where you grill them yourself. Let the staff show you how to place the shells on the grill. When they open you pull off the top part of the shell and put sauce on them. They will cook in their own shell.
We also ordered squid (ika) and grilled it at our table. It is very tasty and tender. Grill the whole squid and then cut it with the scissors. It should be ready in just a few minutes.
You can also eat sashimi here, grilled fish like hokke, and fried fish like tuna steak with garlic. Take a look at the pictures here to get a better idea. http://www.isomaru.jp/menu/
These pictures are from one of their izakaya in Asakusa, Tokyo. This one and most of the isomaru stores are open 24 hours, very convenient if you are out in the afternoon or late in the evening.