The real feat of Hairspray, Adam Shankman’s adaptation of the bouncy Broadway take on John Waters’ 1988 film, has less to do with its competence as entertainment than its willingness to convert grotesque parody into heartfelt conviction. The idea of such an accomplishment took root in Waters’ original work, but at the time, viewers found that it wasn’t easy to see the story -- of a fat teenage girl in the 1960s who uses her newfound fame on a local television show to help the oppressed black community -- as a sincere plea for equality from Waters, the guy responsible for transvestite Divine eating feces in Pink Flamingos.

Reasonably enough, Waters emerges in the first few minutes of the new Hairspray for a fleeting cameo that gives the film its raunchiest moment, as if serving as a reminder of the underlying force responsible for the project. Then it launches into a warm embrace of humanistic ideals in ways the cult filmmaker would never bother to approach. In his marvelously esoteric obsession with outsiders, Waters draws inspiration from the likes of bohemian pariah Jack Smith. But the musical Hairspray is closer to the vitality of the lavish Hollywood productions that Smith’s avant-garde creations naughtily deconstructed. Its brash subversive edge hides beneath the rhythms.

And oh, those rhythms. The last reasonably well-done musical film was Rob Marshall’s 2002 adaptation of Chicago, where the seedy aura of the windy city’s underground nightlife in the Roaring Twenties came through in heavy doses of intimidating clubhouse pizzazz. In contrast, the bright colors and giddily upbeat pop tunes throughout Hairspray carry an inspired sense of fun that recalls the liveliness of a classic Broadway sensation. It’s easy to see how a fluffy project like Hairspray could get squashed by the distinctly separate boundaries of film language, but the movie finds a solid balance between a gloriously stagy feel for its big numbers and old-fashioned movie magic to lift the overall feeling to the level of a big-screen sensation. It offers a fleeting excitement, but an impressive one; the movie might not change your life, but it’s sure to brighten your day.

Cheesy? Perhaps. But the sense of social responsibility, deeply embedded in Waters’ original plot, molds well with a sunshine disposition. The chubby young protagonist, high school student Tracy Turnblad (promising newcomer Nikki Blonsky), serves as an all-American hero for whom everyone can cheer -- and bipartisanship at the movies is a rare delight.

Despondent over her unsuccessful audition for a spot on a daytime television dance show, Tracy satiates her need to move and shake by bonding with the boogying members of the African-American student body, particularly the suave and talented Seaweed (Elijah Kelly). Noticed by heartthrob Link Larkin (High School Musical’s Zak Efron), Tracy is encouraged to import her urban beats to the show’s producers, which leads to her successful recruitment to the cast and builds her local acclaim. But upon discovering that the show’s black performers, led by “Negro Day” host Motormouth Maybelle (Queen Latifah), have been compromised by racist showrunner Velma Von Tussel (Michelle Pfeiffer), Tracy leads a revolutionary movement in favor of balanced values. It’s a two-pronged battle; Von Tussel’s real motivation is to clear the battlefield so her equally snobby daughter (Brittany Snow) can win the upcoming hairspray competition, so class issues and unfair social hierarchy are both at stake. A fierce and oftentimes moving confrontation unfolds, with catchy harmonies paving the way to righteous victory.

That Hairspray spins an endearing yarn is nothing unexpected, but the casting choices this time around bring renewed energy to the events. Blonsky has the right moves and an endearing grin that suits her character; at the other end of things, Pfeiffer is appropriately icy. Jerry Stiller, who played Tracy’s father in the original film, turns up in an amusing role as a dress salesman.

But the real casting accomplishment of Hairspray, as you may have heard, comes from John Travolta, buried underneath pounds of fake fat and shapely clothing as Tracy’s obese mother. New Yorker critic David Denby has called the decision not to give the role to flamboyant performer Harvey Fierstein, who supposedly translated Divine’s performance in Waters’ film into Broadway dynamite, an “idiocy.” I haven’t seen the show, so I can’t make the comparison myself -- but, God, how wrong he must be. Looking very comfortable playing a woman with credible insecurities and a few dance moves of her own, Travolta has come full circle from his Grease days. The actor demonstrated newfound range as a hit man in Pulp Fiction and thus landed a “comeback.” But in Hairspray, he proves that the original sensationalism that brought him fame still beats at the heart of his abilities. The scene in which Travolta’s Edna Turnblad belts out her love for zany hubby Wilbur (a fantastic Christopher Walken) in the hilarious “(You’re) Timeless To Me” shows an honest commitment to the role and merciful avoidance of self-parody.

The enjoyability factor that keeps Hairspray afloat owes much to Shankman, working double time as director and choreographer. The set pieces are a far cry from anything in the oeuvre of Busby Berkeley, but there’s a positive flow of storytelling that keeps the transition between song and dialogue continuous. Shankman’s previous directorial work has less prestige or relevance to it (unless you can make an argument in favor of sitting through Cheaper by the Dozen 2), but the sitcom silliness of his earlier films suits Hairspray surprisingly well. Rejoicing in the sleek Americana of an era enlivened by the rockability spirit coming alive in the country’s youth culture, Hairspray benefits from a light touch -- and offers a backhanded slap to anyone cynical enough to challenge its integrity.