At CEDIA Stewart was showing a rear-projection screen that uses two layers of safty glass with a filmscreen material sandwiched inbetween. They call it StarGlass, and among the possible applications is outdoor use. You could hang a slab of it from the eves of your house such that it was suspended in front of a window. You can then project the image from inside the house through the window and through the StarGlass. Water can't hurt the screen and it's not subject to yellowing, scratching or fading. Just break out the Windex bottle before an evening of patio or poolside entertainment. Better yet...why not replace the glass in the sliding doors to the Patio with StarGlass. They'd be tinted, so no one would accidentally walk into them. There might be occassions when you would want to put the projector outside and watch a movie or sporting event on the inside. Maybe you could build the screen into the side of a shed or Pool House and use it as a tinted window when it's not functioning as a screen.