Visiting Tsukiji Fish Market: One of the largest wholesale fish markets in the world, this indoor market bustles with activity from about 3am on as frozen tuna is unloaded from boats, auctions are held, and vendors sell octopus, fish, squid, and everything else from the sea that's edible to the city's restaurants. Be sure to bring your camera.
Attending a Baseball Game: After sumo, baseball is Japan's most popular spectator sport. Watching a game with a stadium full of avid fans can be quite fun and can shed new light on America's favorite pastime.
Seeing Tokyo from the TMG: On the 45th floor of the Tokyo Metropolitan Government Office (TMG), designed by well-known architect Tange Kenzo, an observatory offers a bird's-eye view of Shinjuku's cluster of skyscrapers, the never-ending metropolis, and, on fine winter days, Mount Fuji. Best of all, it's free.
Hanging Out in Harajuku: Nothing beats Sunday in Harajuku, where you can begin the day leisurely with brunch and then stroll the promenade of Omotesando Dori, shop the area's many boutiques, take in a museum and perhaps a flea market, and then relax over drinks at a sidewalk cafe and watch the never-ending parade of humanity.
Shopping for Japanese Designer Clothes: Japanese designer clothing is often outrageous, occasionally practical, but mostly just fun. Department stores and designer boutiques in Aoyama are the places to try on the styles if you have both the money and the figure for them.
Spending an Evening in an Entertainment District: A spin through one of Japan's famous nightlife districts, such as Shinjuku or Roppongi in Tokyo or Dotombori in Osaka, is a colorful way to rub elbows with the natives as you explore narrow streets with their whirls of neon, tiny hole-in-the-wall bars and restaurants, and all-night amusement spots.
Seeing Fish Eye-to-Eye in an Aquarium (Nagoya, Toba, Osaka, Kagoshima, Beppu, Okinawa): Because Japan is surrounded by sea, it's no surprise that it has more than its share of aquariums, many with innovative displays that put you eye-to-eye with the creatures of the deep. My favorite is the one in Osaka.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.