Off Beat: Do re MI ‘Sound of Music’ Sing-A-LongBreak out the lederhosen, warm up the vocal cords and get ready for some interactive audience fun with Friday’s ‘Sing-A-Long-A Sound of Music.’By Ray Routhier email@example.comStaff WriterDoes the perky, pure-of-heart Maria make you want to cheer?Do you feel like booing every time you see the Nazis trying to ruin the lives of Maria and her newfound family? Do you hiss when you see the smarmy baroness trying to steal the love of Maria's life?If you answered “yes” to the above – if the film “The Sound of Music” makes you want to cheer, boo and run through Alpine meadows while singing about goatherds – then Portland Ovations has the perfect show for you.It's called “Sing-A-Long-A Sound of Music,” and it's scheduled to play Portland's Merrill Auditorium on Friday.“Sing-A-Long-A Sound of Music” is a touring event that not only allows people to sing along with the 1965 film version of Rodgers and Hammerstein's classic 1959 musical, it actually encourages audience members to cheer and boo at key moments.Fans are instructed to wave props like bits of edelweiss and pieces of curtain fabric, to dress like the film's characters, and to even pop confetti into the air when Maria and Captain Von Trapp kiss for the first time.“It's basically like ‘Sound of Music’ meets ‘Rocky Horror Picture Show,’ ” said Erin Schwab, a singer and performer who serves as the event's on-stage host. “There are things to yell out at certain times, things to hold up, just a lot of audience interaction.”Not to mention that the lyrics will be printed on the movie screen, so there will be no excuse for anyone to not sing along. “Even the Latin lyrics, for that scene in the church, are written out for everyone,” said Schwab.“The Sound of Music” has a built-in audience, given that generations of folks grew up watching the movie on TV, video or DVD, and already know all the lyrics. The film, which won the Best Picture Oscar in 1966, starred Julie Andrews and Christopher Plummer and featured such classic songs as “My Favorite Things,” “Do-Re-Mi” and the title tune.