After stumbling onto Backyardtheater.com in late June, we were hooked! On July 14th, after dozens of "test nights" and many screen/sound iterations, the Spring Avenue Starlight welcomed its first non-family guests.
Here is a picture of our theater area as it was BBYT (before backyard theater)...

Here's the "after":

The screen is 16 X 9, 1" EMT frame with Trapeze Plus. The sound is a Sony 5.1 800 watts and I replaced the center speaker with two Bose 201's wired in parellel. Those with sharp eyes will also notice a fresh coat of paint on the garage door!
The frame is 1" EMT with 90-degree corner pieces:

The *perfect* place for the projector turned out to be smack-dab in the middle of my wife's flowerbed. Knowing better than to plop a table down there, I built a swing-arm for the projector and placed one stepping stone in the garden so I can fiddle with focus after swinging it into place.
(the really perfect place for the projector was my son's bedroom window above...would have been just like a projectionist booth!)

Although the "droop" of the swing-arm insults my engineering DNA, it's perfect from a projector-alignment perspective...I just have one thin door shim under the projector for height adjustment.

We had about 50 folks attend our first show...here's a shot as the crowd was starting to take seats...most are still behind the camera, at the bar.

Lessons Learned:
1) Trapeze Fabric Rocks!
2) Stretching the screen in 10-15 mph wind is a ^$*%@
3) Blazing Saddles is soooooo politically incorrect!
4) Stock more vodka, less rum.
5) Don't leave the trash bags outside for even 15 minutes as you clean up...animals are fearless.
6) Everyone on this forum was correct...size does matter, sound does matter, but mainly only to the owner...everyone would have had just as much fun with shadow puppets, it's getting together that is the point!
Thanks to everyone here who contributed knowledge to make the Spring Avenue Starlight Theater a success!
Dennis