Some of the more unique and enjoyable examples I can think of include:
- Dillon, Colorado. The audience sits on a hill with the stage at the bottom, near a lake. The back and sides are open, so the backdrop is a gorgeous view of the lake and mountains.
- Jerome, Arizona. This is a WPA-era project The seeting is located on a hill that faces the principle commercial block. The street is used as the stage. It is a good one for hosting events in the downtown.
- Whitewater, Wisconsin. The stage is permanent, set at the base of a small rise, with the lake in the background. The backdrop is made from panels that can be removed when not in use, to keep the view open.
I have photos of these and others. PM me if you are interested.