Even if you’ve never been to the Sing-a-Long Sound of Music, surely you know what it’s all about — it’s not rocket science, after all. But it is fun. And camp. And we’re betting you even know the words to all the songs from the classic movie musical, from “My Favorite Things” to “Sixteen Going on Seventeen” to “Edelweiss.” However, if you’re a bit rusty, rest assured the lyrics will be shown as part of the movie on Wolf Trap’s huge screen. The outing includes a Sound of Music-inspired costume contest and there will even be a goody bag filled with props for use during the show. This Saturday, Aug. 23, at 7:15 p.m. Wolf Trap, 1551 Trap Road, Vienna. Tickets are $25 to $38. Call 877-WOLFTRAP or visit wolftrap.org.