The enthusiasm of "Matsuri," booked at the Riviera at least through April, pulls you right into the exuberance of the youthful, 33-member troupe. Photo by Ralph Fountain.

You'd better be mighty good or mighty different to open an acrobatics show in a town with four Cirque du Soleils and a fifth on the way.

"Matsuri" is both those things and what's more, it's relatively simple -- at least if you're watching it instead of trying to explain it. One runs into quite a few people who say "Mystere" is still their favorite Cirque title, because of its direct connection with the audience.

Those same people, I think, will like this one for the same reasons. Some parts of the Japanese revue are familiar and some are strikingly original. But they're all delivered with an enthusiasm that pulls you right into the exuberance of the youthful, 33-member troupe.

"Matsuri" is booked at least through April as an afternoon show at the Riviera, testing its draw outside of Japan. There it's an ongoing hit known as the Muscle Musical. As best as I can figure, it's the same way we used to know Cirque du Soleil by only that name until it grew to the point where they needed to distinguish the shows.

The manic revue unfolds with people in bright costumes, and sometimes red or purple-dyed hair, doing crazy things to frantic music. For instance, there's a jump rope. A really long jump rope that goes from one side of the stage to the other. After a few people jump it in the expected way, a guy jumps it while doing a handstand. Then another guy comes out and jumps it while riding a bicycle.

Later, they get rid of the rope altogether and turn one of the shorter, female members of the troupe into the jump rope.

A couple of the performers get what amounts to solo segments. Each time Daisuke Nakota bounces up on his trampoline, he writes on a wall until he has spelled out "I Vegas."

Keigoh Arizono is the mountain bike jumper who leaps nimbly over a supine colleague. Yasuaki Yoshikawa spins around inside a giant wheel, making it look so easy you'd like to take it outside and try it yourself.

But the most memorable sequences are the ensemble efforts. One begins with a ballerina (Ayuri Iisaku) encountering a single silver ball. Soon the stage is covered with them, and a guy is "flying" across them like Superman.

In a rare dramatic moment, the barefoot male ensemble stomps on wooden boxes while hammering sticks in the air to simulate the sound of taiko drumming.

But the sequence that may best encapsulate the show's blend of athletics and physical comedy has a woman plunking out simple melodies on an electric piano, causing the men wearing piano "keys" on their backs to respond with push-ups and grimaces.

Not every moment of "Matsuri" is that rewarding. Even at an hour's length, it feels slightly padded. And the original music -- by Kajuhito Fujiki and Takayuki Ohkubo -- can be grating on Western ears, sounding too much like one of those "Hooked on Classics" aerobics tapes from the '80s.

The production isn't helped by the tinny sound and limited lighting system of the Riviera showroom, where it has to share backstage storage space with "Splash." You can imagine that if "Matsuri" found a permanent home on the Strip, there'd be a great temptation to really gussy it up and Westernize it.

But any such task would have to be approached with caution, because its odd foreign quality is key to the charm of how it wins you over. You wouldn't want it to get too slick. Remember we already have all those Cirques.