Stop in for a cup of coffee

Its supposed to rain on Saturday at the Car show. Last time my windshield gasket leaked so bad I had 2 inches of water on the floor. Does anyone have any ideas of what to use to cover the car? At least the roof to cover the front and back glass.

Do they make water proof car covers?

Someone makes a kind of throwaway thin plastic one... I will see if I can find a link to it.