Imagine a way to burn a ton of calories, save your knees, work your core and quads, have fun, and stay in the air conditioning.

No, we're not talking about Wii Bowling. We're talking about trampoline dodgeball.

A company called Sky Zone is building these indoor playgrounds entirely of trampolines for 3-D dodgeball, SkyRobics, basketball and just plain "open jump." And these bouncy wonderlands are attracting everyone from gymnasts to the elderly to -- of course -- kids. (Moonwalks are quivering in fear.) Sky Zone started as a class project at Washington University's Olin School of Business, but investors jumped (ha!) at the opportunity. Now franchises are opening almost as fast as the guys in this video can launch a squishy ball.

"We get all kinds of customers," says Anthony Woods, assistant manager of Sky Zone in Rocklin, Calif. "Of course for 3-D Dodgeball, we have to separate by sizes to keep it fair. It's really popular with the 16-and-up crowd."

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Spinning and boot camps might burn a ton of calories, but they certainly don't make you feel like you're flying. Woods says an hour or so of playing at Sky Zone can burn up to 1,000 calories, depending on your size and fitness. He claims you have to use 30 percent more energy to balance and move in the Sky Zone. And if you've ever used a Bosu ball, you probably see the logic.

"We've had 90 year-old men come in and use the Sky Zone for tumbling," Woods says. "It's very low-impact."

Take it from your elders: You don't have to wear butt-toning sneakers to get a great workout. Though if you run into these cats, you might have to wear a helmet.

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