* The problem: You are stuck at the airport (like, say, Chicago O’Hare) with some hours-long delay. ARGH. If only you could running. Laps inside the airport terminal are a possibility, but (1) it’s not clear that TSA wouldn’t frown upon that; and (2) you have to lug your stuff. If only more airports had their own gyms (ironically, O’Hare is one of them). Airport Gyms tries to remedy that problem by listing gyms nearby most major…