Tracy Turnblad (Nikki Blonsky), the heroine of Hairspray, is a sweetly perky high school girl with a pasty coif that flips up on each side, a grin as bright as an electric billboard, and a mood so bubblicious she's like the teenybopper Shirley Temple of 1962 Baltimore. When Tracy, who can barely focus in class, goes to audition for The Corny Collins Show, the local afternoon TV bandstand around which her life revolves, she swings, twitches, and rocks her body with jubilant abandon. This makes for a rather startling image, given Tracy's undeniably bounteous physique. Yet when she does the twist, the frug, or the mashed potato, flinging her arms back and forth, her butt twitching furiously in a tight plaid skirt, she's not just a great hoofer she's dirty-dancing on air. In her very heftiness, she makes you feel the mad, cool acrobatic joy of each unhinged gyration.
Hairspray is a fizzy and delirious high-camp message-movie musical that may just turn out to be the happiest movie of the summer. The opening song, ''Good Morning Baltimore,'' sets the tone: As Tracy skips through the city, singing a girl-group ditty whose big beat and Oh-oh-ohs evoke ''Be My Baby,'' the music is pure infectious pastiche, studded with enough good hooks to get your heart bopping and a few kinks, too, like the image of Tracy atop a garbage truck. Adam Shankman, who directed and choreographed the film, is a prosaic visual stylist every scene has the same overbright high-gloss finish yet he's an alchemist of movement, of high spirits made flesh, and the numbers are so exuberant they give you a tingle.
The movie was adapted from the smash-hit Broadway show (first staged in 2002), which was itself based on John Waters' blissfully cracked 1988 screen comedy. In the original film, Tracy, played by Ricki Lake, stood in for every outsider, as she joined with the black kids from the ''wrong'' side of Baltimore, who were allowed on The Corny Collins Show only on Negro Day. The Waters movie was an anti-bigotry boogie: Tracy and her friends, with their ''race music'' moves, were the freest dancers around, and only prejudice could keep them down. That same theme dominates the new Hairspray, but with an arresting difference: Since the picture is a musical, and the unlikely image of Tracy the plus-size rock & soul whirligig is even more front and center than it was before, she's now thrilling to watch because she alone understands that pop dancing isn't about how you look while you're doing it but how you feel.
That's a message we still need to hear in an age of robo pop stars who have more cachet as fashion plates than as artists. In detention, Tracy and her pal, the uptight Penny Pingleton (Amanda Bynes), meet the sexy pomaded Seaweed (the electric Elijah Kelley), who dances like James Brown with wings. Tracy cops a few moves from him, and once she lands a spot on Corny Collins, her glee starts to spread everywhere, igniting a teen-integration war. Yet the heat really begins at home, where her walrus-bodied mom, Edna, played in a triumph of casting by John Travolta, develops from a stringy-haired agoraphobe hooked on diet pills into a vision of ''liberated'' glee. From the start, Travolta, with dottish small eyes set in a big round pancaked face that makes him look like Petunia Pig, throws us for a loop by underplaying. Speaking in a Baltimore accent that rounds each ''O'' into a plea of concern, he makes Edna tender, naive, and touchingly dear a woman of big appetites yet tiny desires, just waiting to find her place in the world.
She finds it in the great number ''Welcome to the '60s,'' in which Tracy and Edna go shopping at Mr. Pinky's Hefty Hideaway, and the emotions of the film bust out. As Travolta starts to move that impossible body, he's a vision of unlikely grace, and you feel the freedom in every shimmy and bounce. Not all the songs work. As Edna's husband, a goof who runs a joke shop, Christopher Walken makes his befuddled detachment fun, but when he and Edna have their big romantic moment, ''(You're) Timeless to Me,'' it's so kitschy the two actors don't quite connect. For a brief period, the movie sags. I wish that Queen Latifah, as the soulful den mother Motormouth Maybelle, were playing less of a saint, and that Michelle Pfeiffer, as the villainous Velma Von Tussle, had a more memorable song to express her dragon-lady WASP disdain. But Hairspray gets its vibe back quickly enough, and the climactic number sends you out on a high. It's called ''You Can't Stop the Beat,'' and by now it applies to a Hollywood musical revival that's in full, glorious swing.