MISSOULA, Mont. -

We've all seen people singing along to the radio at stop lights, but how about dancing? One Missoula-born dance phenomenon is taking over, and it's causing people everywhere to break out in dance while they're shopping, working and even driving. We're talking about Oula.

People cram into Missoula's Downtown Dance Collective on their lunch break every Wednesday.

"It isn't a dance fitness class. It's Oula," said Crystal Smith, the marketing director for Oula. "It's an experience. It's this thing that touches people."

UM graduate Kali Lindner started Oula in 2010 when she couldn't find a fitness class that combined everything she was looking for. Smith took one of her classes and pushed her to expand.

Oula is a cardio dance class that combines the spiritual aspects of yoga mixed with a playlist of top music hits. Oula regulars see the physical results, but Lindner thinks it's the emotional connection that keeps them coming back.

"You know those moments when everyone is just in it together and that's really, really powerful," Lindner said. "And that, to me, is what makes Oula feel so good. It's what everybody does together."

Now, the class can be taken at 12 Missoula locations along with spots in Helena, Bozeman, Michigan, California and British Columbia. Up next? The Flathead and Seattle. Lindner still can't believe the success.

"If I go into a class where there's not as many people that day, I'm like, 'we're done! They're sick of us. The ride is over!'"

But they're far from being over. The Oula Facebook Page is just one piece of proof. The founders started flash mobbing places in Missoula to connect with the community. Smith's teen daughter just has to look the other way when her mom publicly breaks out into dance when an Oula song comes on.

"I think it's a really special thing for kids to see their moms and dads being silly, like turning up the music, rocking out, teaching their kids the dance moves," Lindner said.

You'll see a sprinkling of men in some classes. Even if men aren't regular fixtures, many support the program in other ways.

"I like it when people are like, 'I was having the worst day and I knew I had to get to Oula,'" Smith said. Lindner added with a laugh, "I know. My husband is like, 'go to class!'"

While it's a Missoula-born business venture, the goal of these women is to keep Oula's roots intact. That means a slower growth.

"If this ended up staying on a much smaller scale but still felt like Oula, then we would have succeeded in what we set out to do," Smith said. Lindner agreed. "That would be success for us."

So these ladies want you to let your guard down, leave your intimidation at the door and just come dance with them.

Saturday night, Oula lovers will celebrate the program's new website launch and connect people in the community. It's an open event being held at 7:00 p.m. at the Stensrud Building in Missoula. There will be prizes, merchandise, drinks and dancing. For more information, click here. You'll find class schedules in the about section of their Facebook page.