We’ve seen them all: hip-hop and salsa step classes, water aerobics, disco boxing – anything to get away from the same old weight-machine shuffle.

But what was new then is already old – and now there’s a fresh crop of newfangled work-outs to tighten up for those slinky warm-weather dresses.

When it comes to wild and wacky workouts, Crunch takes the cake – and the popcorn, balloons and clowns – at Circus Sports.

After warming up with handstands, back bridges and Hula-Hoops, students at a recent workout started to tumble – and bunny-hop, scissor-kick and wheelbarrow their way across the mats. Before long, they were walking on their hands and somersaulting through hoops.

“I love this class,” said Etta Valeska, who has seven Circus Sports classes under her belt. “It makes you feel like a kid.”

Not only that, said fellow student Monica Vela, it works. “I swear I’m seeing more results from this class,” she says.

Sarah East Johnson, who trained with the San Francisco School of Circus Arts and New York’s Circus Amuck before signing on at Crunch, said the class is all about “trust, timing, coordination and complex moves.”

Students need those skills to master a full-size circus trapeze that hangs about six feet from the ground.

“This class really keeps the mind working,” Johnson added. “It’s not rote repetition.”

Fresh from Los Angeles, it’s Crunch’s Karaoke Spin class.

Instructor Lori Benson dons a microphone headseat seated atop her stationary bicycle on a colorfully lit small stage, while her students spin in near darkness – making it easier to just go ahead and grab that mike.

Everyone sings backup while a bold spinner belts out her favorite song, punctuated by Benson’s “Uh, huh!” and “Oh yeah!”

“I always tell my students that they’re working out twice as hard – they’re using their bodies and their voices,” says Benson. “And no one cares who can sing.”

“It’s totally fun,” said Theresa Stallworth, who took a turn with Prince’s “When Doves Cry.”

“And the results are amazing!”

And you thought yoga was all deep breathing and meditation. Not when Trixie teaches Disco Yoga.

“Trixie” – the persona that Crunch yoga instructor Dana Flynn adopts when she teaches this class – works in a darkened room with a disco ball and occasional red strobe light picking out the back beats of Donna Summer and Marvin Gaye.

“Enlightenment [a basic principal of yoga] is all about lightening up, not taking everything so seriously,” Flynn said. “In this class, we play around with movement and combine the breathing and postures of yoga with some great music.”

“Trixie’s fabulous, she’s really inspirational,” said student Jasmine Talkeshi. It’s still the yoga experience, but taken out of its rigid form. There’s a real freedom to go all out.”

For another twist on yoga, try the New York Health & Racquet Club’s class, Layla’s Garden, in which instructor Deedee Benrey mixes things up with Persian poetry, Iranian foods and juices, yoga exercises, self-massage techniques and… rock songs.

Eric Clapton, who named his Layla after the same Persian love story the class draws its name from, provides the background music for Benrey’s meditation ritual.

Then again, maybe meditation isn’t your thing. If you want to step lively, the NYH&RC’s Broadway Dance Series has professional dancers from shows like “Annie Get Your Gun,” “Chicago” and “Kiss Me Kate” teaching you the actual steps (toned down a bit) from real Broadway shows.

“We use a lot of funky western dance steps,” said Madeleine Ehlert, an “Annie Get Your Gun” dancer and instructor. “There’s a lot of horse-stepping and gun fingers.”

If Broadway-style hoofing isn’t enough to burn off that flab, the New York Sports Club offers a Cardio-Video Class with a dancer who’s made videos with Whitney Houston.

Sheryl Murakami teaches punchy, strutty, fun moves to the sounds of Method Man and ‘N Sync.

Beginners, beware: Tight, muscular participants who were clearly in shape at one class were dripping with sweat by the end – and one person even walked out.

“I teach professional dance moves heavy on the cardio,” said Murakami. “It’s a good time. You leave feeling like you really just danced in a video – you learn the latest moves.”

More novice-friendly is the Urban Athlete class, also at New York Sports Club.

The class starts with jumping rope – an indoor version of street double-dutching. Next, you’ll face the cone gauntlet to prepare you for construction projects, congested areas and a summer of grid-locked tourists. If one of those tourists should get testy, kickboxing and punching moves are taught for self-defense techniques.

And if you shape up enough, you may need all the self-defense techniques you can get.