Really, ten hours is too long to spend in the airport, even if you plan to spend two days in Tokyo.

I lived in Tokyo in the 1970s, and I've lost track of how many times I've been back for long or short visits, and I still haven't seen everything. A mere two days? You're not even scratching the surface.

Get a guidebook and figure out what in Tokyo is most interesting to you. The monorail ride to Haneda is fun in a retro tech way, and it lands you at Hamamatsucho Station, which is on the amoeba-shaped Yamanote Line around the central city. You can make a full circle in about an hour, and several worthwhile sights are located near its stations.

For example, if you're into electronics and anime, Akihababara is a great place to spend a couple of hours. For a more traditional Tokyo, the area around Ueno offers lively street life within a few blocks. If you're there on a weekday, you may have just the right amount of time to get off at Shinjuku, transfer to the Oedo subway, and travel one stop to the Metropolitan Government Building at Tochomae, to go to the free 45th floor observation deck. For something more relaxing, the Hama Rikyu Gardens are near Hamamatsucho.