For a sushi lover, a trip to Tokyo isn't complete without a trip to the famous fish market Tsukiji.
If you're willing to wake up at 3am and get in line, you may be able to watch the world famous tuna auctions. If you want to skip the tuna auction, the market opens up at 9am to the public; although, by 9am most of the fish is gone. Still, though, walking through the market is a pretty exciting time, just make sure to stay out of the way of the workers.
Sushi for breakfast may sound weird, but most of the sushi joints in the surrounding area of Tsukiji close around noon.
The most popular place, Sushi Dai, generally has a line that starts at 4am and doesn't go down until closing. The wait is usually about 2-3 hours. Honestly, most of the places in the area serve comparable sushi, so if you don't want to wait just wander into another place. Daiwa Sushi is a good alternative and located next door to Sushi Dai. There is usually a line outside of Daiwa as well, but the line goes much faster and the sushi chefs and sushi are both great. For ¥3,500 you can get the set, which comes with miso soup, seven pieces of nigiri and six pieces of makki sushi.
To get to Tsukiji take the subway to Tsukijishijo station on the Toei Oedo line.