We've spent alot of time on the subway this week, and while we were waiting for the Q one day, we came up with this very simple but fun (to us at least) game involving the subway maps that you probably ignore most of the time. Step 1: ask her to find Central Park on the map, then Coney Island, JFK, etc. There is no Step 2. Simple, but a good way to buy ten minutes of not hearing "I'm bored" and "when is the train getting here?", plus teaching a bit of geography.