OKLAHOMA CITY - It's every explorer's dream: darting through underground passageways, discovering new colors and features with every turn.

A version of that scenario will be offered Saturday with the first Riversport Runderground - a 5K fun run through downtown Oklahoma City's underground tunnel system. The non-timed event will take runners through most of the underground, beginning and ending at the Cox Convention Center. The event is a part of the Bart and Nadia Sports & Health Festival, which gathers numerous healthy activities and partners under one roof.

Sherry Andrusiak, a spokeswoman for OKC Riversport, said because that organization connects people with all kinds of activities at the Oklahoma River - including the 13-plus miles of trails alongside it - a fun 5K event seemed fitting for this year's festival. And the underground seemed a perfect wintertime setting.

"It's indoors and it's a space that, since it was revitalized, reflects a lot of the history of downtown," Andrusiak said. "It's a neat space, but unless you work downtown, you might not even know it's there. So it will draw people in to see it - the art galleries and historic photographs that are down there - and they'll get another taste of the uniqueness of downtown Oklahoma City."

The run starts at 9 a.m., and registration comes with a T-shirt.

Runners wind back up at the Cox Center, where Bart Conner and Nadia Comaneci's health extravaganza takes place. Conner said the festival grew out of a desire to bring several sports and health programs under one big umbrella.

"We have been running gymnastics meets in downtown Oklahoma City for the last four or five years, and we kept thinking, ‘What if we did something a little broader and more impactful related to not just sports but health and wellness?'" Conner said.

He teamed up with The Oklahoman, which had been holding a health festival, and the University of Central Oklahoma, which offers sports for people with physical disabilities. The result is an event with something for everyone, from health screenings to gymnastics to indoor kayaking and rowing. The festival is geared toward families with a special emphasis on youths.

"If kids get excited about sports and fitness - if they get excited about ownership of their health, I think it makes a big difference," Conner said. "Kids who get involved with competitive sports at an early age have health and wellness as part of their mindset. Today I'm going to eat, sleep, and I'm going to exercise, and that's just part of what you do. We want to keep reinforcing that here - to get kids to understand obesity, high cholesterol, high blood pressure - but also to learn fun, interesting and maybe nontraditional ways to stay healthy and fit. They're going to be exposed to things they might not otherwise see, like rowing, kayaking, gymnastics, sitting volleyball and archery."

The Bart and Nadia Sports & Health Festival is Feb. 11 to 13. For a complete list of activities, visit http://www.bartandnadiafestival.com/. Registration and information about the Riversport Runderground is at http://riversportokc.org/