Sports and leisure
Gold's Gym - Sports facility: Harajuku [Open 24 hours a day.]
If you're jetlagged or working late but you still want to get in a workout, the branch of Gold's Gym in Harajuku is open 24 hours a day* and offers a one-day pass for non-members. There's a good range of weight-training and cardio equipment,...
Leisure Land Palette Town - Sports facility: Aomi [Open 24 hours a day.]
Open 24 hours a day, this well-equipped game arcade is the place to go for after-midnight bowling and late-night ping pong in Tokyo Bay. Apparently baseball players don't stay up so late - the indoor batting range is open only from 10am-11:50pm.
Lotte Kasai Golf - Sports facility: Kasai Rinkai Koen [Open 24 hours a day.]
Ninety-minute unlimited drive packages are available at certain hours, or you can pay by the ball (Y16-22 depending on time of day). Note that while the facility is open 24 hours a day, they take a 45-minute maintenance break every day from...
Onsen
LaQua - Onsen: Korakuen [Open 11am-9am (spa area) daily.]
The LaQua complex, part of Tokyo Dome City, features a hot-spring spa and a shopping center with more than seventy shops and restaurants, interspersed with a handful of amusement park rides. The baths feature sodium-chloride-infused natural...
Oedo-Onsen Monogatari - Onsen: Aomi [Open 11am-9am (enter by 7am) daily.]
If Tokyo Disneyland had a 'Onsen-land' section this is what it might look like. "Soak in the ambiance of old Edo town life at one of Japan's largest onsen hot spring resorts." says the pamphlet. This pricey onsen caters mostly for day-tripper...
Note: The onsen listed here are closed from 9-11am.
Retail
Don Quijote Ginza-ten - Retail: Shimbashi [Open 24 hours a day.]
A 24-hour branch of the intriguingly eclectic discount store chain.
Jeans Mate - Retail: Ikebukuro [Open 24 hours a day.]
The place to shop for jeans and other casual clothing in the middle of the night.
Yamashita Books - Bookstore: Shibuya [Open 24 hours a day.]
A 24-hour branch of the Japanese bookstore chain.
Services
Kinko's (Akasaka-Mitsuke) - Service: Akasaka [Open 24 hours a day.]
24-hour copying, printing, delivery drop-off and other office services