DAYTON — This, for me, is the defining moment in Sing-a-long Sound of Music, the demented interactive entertainment unreeling through Sunday at the Victoria Theatre:

        Julie Andrews fills the screen as nun-in-training Maria, fuming over widowed party-pooper Captain Von Trapp who won't let his seven motherless children play. The entire audience breaks out not in song, which would be an option, but with advice. “Julie! the curtains! Julie! Look at the curtains!”

        The generation that invented the movie as an interactive entertainment genre with The Rocky Horror Picture Show is all grown up and slowing down. But not so slow that we can't have a good time with a movie that baby boomers grew up with and know by heart.

        Sing-a-long is a laugh-out-loud hoot, starting with the mostly-accordions orchestra playing outside the theater before the show. Then there's the warm-up, deftly led by emcee Tim Lile in lederhosen, and the costume contest.

        On opening night, the competition included rival warm woolen mittens and brown paper packages tied up with string. A ton of nuns (literally — I counted 27) were eliminated early. The wimpled women were all wielding rulers, which may have been a disqualifier. It's American, not Austrian, nuns who carry wooden sticks.

        A special feature on opening night was an appearance by Charmian Carr (she was 16 going on 17 in the movie). She helped Mr. Lile explain the Participation Procedures, although the audience was ahead of them and cheerfully expanded on their suggestions.

        It's good, clean fun. Emphasis on clean. We cheer Maria, boo the evil Nazis, hiss the Baroness, coo over little Gretl, bark and snarl at Rolf, the bicycle messenger-turned-Nazi youth. And, of course, we sing.

        The lyrics are printed on the screen (sans bouncing ball) and we enthusiastically sing along (although on opening night nobody joined the on-screen nuns in the Latin number at the abbey).

        Singing is just the beginning. We learn a whole set of gestures to go with“Do-Re-Mi,” and everybody in the audience gets a Fun Pack filled with all sorts of good stuff, like fake edelweiss (it's a plant) and an invitation to the Captain's Ball. (Hiss the Baroness!)

        While there were youngsters in the audience on opening night, there weren't as many as you might expect. A lot of the audience were clearly happy to revisit their youth without kids in tow.
        Sing-a-Long Sound of Music, through Sunday, Victoria Theatre, 138 N. Main St., Dayton. (937) 228-3630.

Parade's official peacemaker
The highest stakes of all
Dr. Heimlich humored by namesake hospital
Paxton's songs keep pace with times
Storytellers thankful it's Fray Day
Audience comes alive to interactive 'Music'
The Early Word
Top 10s
Get to it