You're not going to believe this, but I saw a neighbor do this and read that restaurants sometimes do it, too - supposedly because it actually works! Hang a plastic zip-loc bag filled with water next to your door. Hers was in the garage by the door. She recommends using two bags, one inside the other so it can hold the weight of the water without busting. Anyway, something about the flies seeing it, keeps them away. Check this out: http://animals.howstuffworks.com/animal-fa...s.htm/printable