The hefty heroine is plucky high schooler Tracy Turnblad (newcomer Nikki Blonsky), whose dream is to dance on “The Corny Collins Show,” Baltimore’s answer to “American Bandstand.” This being 1962, it’s a whites-only affair, with one “Negro day” allowed a month, and even that much displeases the nasty, racist and very thin Velma Von Tussle (Michelle Pfeiffer, relishing her villainy). Velma, the station’s manager, is also the pushy mom of the show’s stuck-up (and thin) star dancer, Amber (Brittany Snow), Tracy’s rival. The commingling of bubblegum drama and social conscience—we’re at the dawn of the civil-rights movement—is handled with finesse and high spirits, though with a trace of the earnestness that Waters would never allow. Travolta, burdened with prosthetics that constrict his expressions and a bizarre Baltimore accent that sounds like Lily Tomlin channeling Ed Sullivan, takes getting used to, but like the movie itself, he’s ultimately endearing. As Edna’s adoring husband, Wilbur (“This heart only beats for a size 60”), Christopher Walken partners Travolta with gusto. Amanda Bynes and Elijah Kelly as the interracial couple Penny Pingleton and Seaweed are standouts in a high-stepping cast that includes a blonde Queen Latifah and a brilliantined James Marsden. A pop period piece that tips its hat to the MGM musicals of old, the sunnily subversive “Hairspray” embraces big bouffants, big bodies, big production numbers and big hearts. Shankman and his screenwriter, Leslie Dixon, prove you can make a lightweight Broadway musical into big movie fun.