Re CURTAINS
I also remember the effective use of the curtain and the area immediately in front of it when I saw Dame Edna on (or off, don't recall which) Broadway. As we were allowed in to find our seats, in front of the curtain was a tiny screen, reminiscent of a home movie projector screen, on which was shown a "documentary" about Dame Edna. The effect was either that it was a home movie or that we were watching an extension of "her" TV appearances on a "small" screen.
Don't know if anyone saw Elvis Costello and his initial run of the Spectacular Spinning Songbook. At the theater I attended, the curtain was used to hide the spinning wheel, the vintage TVs and the Go-Go cages. When we were allowed to fill our seats, the theater's sound system played polka music, which really confused us and set us up for almost anything. The opening act performed in front of the curtain. The opening of the curtain was for the main show and star revealing the items on stage that didn't make sense at first.
During one of my breaks between treatments/hospitalizations last year, my friends treated me to the IMAX presentation of "The Wizard of Oz" for its 75th birthday, a bit early yes, but very magical because at the theater I went to, there was a curtain. There was of course the usual coming attractions for 3D, etc. However, as soon as the theater went darker that extra bit just before the main feature is shown, the curtain was pulled in to make the screen appropriately smaller for a 1939 movie. I'm sure this was all computerized. The curtain moved as the very first notes of the overture began as if to emphasize the specialness of what was being shown.