Monty Hall

Behind the doors are two booby prizes (banana skins) and one star prize (a sports car). Can you win the prize? First choose a door. Monty will open one of the other doors to reveal a booby prize. You can stick with your original choice or switch to the other door.

Does it make a difference whether you stick or switch? What are the chances of winning if you always stick or if you always switch? from Shodor