As we process applications for the 2010 Inc. 500 | 5000, 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. One that caught our eye was the Cincinnati-based Time Timer.

Founder Jan Rogers, 65, is a firm believer in the old adage: "Necessity is the mother of invention." She was tired of answering her daughter Loran every time she asked that all-too familiar question, "How much longer?" So she came up with a new type of clock that gives kids a more concrete notion of what time is.

Rogers' invention, which she called the Time Timer, is a clock that uses color to count down the minutes in an hour. It starts as a full red circle, but as the minute hand moves clockwise, the circle opens revealing white space. Kids can then understand that the white space represents all the time that has already passed, and the red space is how much time is left.

"It was just obvious to me that it was a real curiosity for her and frustrating as well, so I wanted to find a solution," Rogers remembers. "I had that naïve idea that if you had a good idea somebody would buy it from you, but that didn't happen, so stubbornness took over, and all of a sudden I was an entrepreneurial businesswoman, and must have had the right instincts, because we've grown ever since."

For the first 10 years, Rogers did almost all of the product manufacturing and shipment from her basement, using double-sided tape to hold the pieces together.

"It was very primitive," she says. "It was just to get it out there, so I could test the market."

Rogers brought the Time Timer to trade shows around the country, marketing her product to niche education markets, from preschool and math teachers to special education teachers and occupational therapists. She says 75 percent of her growth in the last 10 years has been the product of word of mouth.

"I realized if I could get one teacher in a school to buy one and become a raving fan, then the whole school would buy them and then the school district would buy them and then the parents within the district would buy them," Rogers explains. "If I decided I was only going to market to preschool, I would have really restricted myself. Just by trying other markets, it spread."

The last 10 years, as the company's reputation has grown, Rogers has also been able to add more products to the Time Timer line, including an iPhone app, watches and smaller versions of the original eight-inch box.

"The more technology became important for basic life skills, the more people needed it everywhere they went, so I've needed to address that," Rogers says of the growth strategy that has allowed her revenue to soar by 45 percent or from $1.8 million in 2006 to nearly $2.7 million in 2009.

"The best thing any entrepreneur can do for themselves," Rogers says, "is believe and persist, and you're probably going to reap some benefits."