Except for the Beatles, no pop act in history had a more brilliant run of singles than ABBA — and the movie version of Sgt. Pepper should’ve scared straight anyone stoned enough to ever again concoct a story line around a hits catalog. The creators of the Broadway-bound (via London, Toronto, San Francisco, and now L.A.) Mamma Mia! ignored this conventional wisdom, and we’re the luckier for it. The book, about a girl using her wedding as a lure to find her real father, is outranked in its flimsy dialogue only by its structural canniness in stringing together Benny and Bjorn’s preordained show tunes. Hearing a cast of 30 belt ”I Do, I Do, I Do, I Do, I Do” is as ecstatic an experience as you’ll get within the limits of the law.