You could probably use the exercise. Look up friends or relatives in the area. They ll appreciate hearing from you. Get together for a couple hours or just chat on the phone. If you re traveling with children, take them to a play area.
Most airports have one, and so do kid-friendly bus and train stations.
If you re alone, play solitaire or do a crossword puzzle. If you have a few hours, pay a cabbie to show you around. You may learn something and have fun while you re at it. The key is to think creatively about ways to spend your time. Plan for it in advance, and pack what you need to keep yourself busy.