As applications for the 2010 Inc. 500 | 5000 arrive, we thought it would be worthwhile to shine a spotlight on some of the companies that are vying to appear on our ranking of the fastest-growing private companies in the U.S. (For more information and to apply, go to http://www.inc.com/inc5000apply/2010/.) One that caught our eye was Seattle-based Twenty20.

The front tire of the motorcycle tilts at an impossible angle on the ice as it pulls through a turn and toward an opponent who is blowing a stream of snow powder behind him. You watch in horror as the man ahead suddenly swerves to the ice and out of the video frame, only to appear smiling and waving from a stretcher in the next shot.

This is just one of many moments in Motorcycle Ice Racing that was made recordable by co-founders Marc Barros and Jason Green's wearable camcorder business, Twenty20. The company makes two versions of a tube-shaped, high-definition camcorder called the ContourHD that can be attached to helmets, goggles, handle bars, or cars to capture adventure sports from the perspective of the participants. "There's been everything from paintballing to cooking," Barros says. "Anything where you have your hands on the wheel, on the pole, or on the gun, and you want to record video."

Almost 50,000 cameras were sold in more than 50 countries last year, and more than 25,000 videos have been uploaded to the Twenty20 site. But Barros and Green didn't imagine they would have such success when they began Twenty20 as students at the University of Washington. At the time, they simply liked to ski and wanted to show their friends what they were doing. They won their start-up capital in a business plan competition. "We got third place, and the prize was 20 grand, so it was either a keg party or a company, and we decided company," Barros says.

From there, they cold-called a designer who they eventually convinced to create a hands-free camera. The original version could be worn on a helmet, but needed to be attached with a wire to a video recorder in a backpack. Sales weren't exactly taking off, the pair was working from a garage with no heat, and Barros's mother asked him when he was going to get a real job.

Things turned around when Twenty20 launched the first wireless wearable camcorder in January 2008, which made it possible for adventurers to film hands-free with the flip of one button and to easily share their video on the company's website. In 2009, the company released two HD versions of the product and received a tremendous response that facilitated the growth of the company to 25 employees. Revenue tripled within a single year, and the days of working in a cold garage and living off of PBJ seemed further away than ever.

"The company took off like a rocket ship," Barros says.