said by davidg:
another option would be to get a car cover and put it on when you park. then simply remove it and voila, no iced up/snowed up windows.
Ah, but make sure it's one made for winter!! I had one last winter but it was more of a pain than it was worth. Not only did the damned thing
freeze to the car but I couldn't get in the car to start it to get it warming up.
To the OP: As stated, the only way is really to just get the car warming and have something warm to drink while waiting. If you really want to be interesting though you could try a sheet of thick plastic and try to figure a way to secure it over the top of the car covering the windows.