Tsukuji fish market is a buzz of activity from the early morning and one benefit of jet lag is that you'll be up early to make the trip to this little gem in Tokyo. You have to have your wits about you though as the action is frenetic and getting run over by a trolley of fish is a real possibility.
By the entrance of the market there are a handful of tiny sushi restaurants. These consisted of just a counter from behind which the sushi chef worked. Now strangely some of these restaurants had huge queues outside whilst others were virtually empty. Given that the majority of these queues didn't look like locals I suspect this was the 'lonely planet' effect. I doubt, to the casual sushi eater, the quality between these establishments would be noticeable.