As far as sing-alongs go, the Sound of Music Sing-Along at the Hollywood Bowl is the Mother Superior of Them All. There you are, sitting under the stars in the cool night air, singing your guts out with 17,000 other nerds, most of them are wearing some sort of Swiss/nun/girl-in-white-dresses-with-blue-satin-sashes get up. Everyone goes bananas when the camera spots Julie Andrews coming over the hill. There are a lot of wolf whistles when the Captain shows up. We boo the Nazis. Rolf is shown all the disdain he deserves. (What a dummy. I don't know what Liesl was even thinking.) And the Baroness gets hissed.
Now, hold on a minute. I'd like to say a word on her behalf ("then say it Sister Margaretta"), her eyebrows demand some kind of respect.