Meet the Whiz Kids: 10 Overachievers Under 21

7. The Chair Man

At age 20, Sean is the oldest wunderkind in our group, but he takes a back seat to no one. And why should he? Six years ago, he started an online furniture business that grossed $38 million in 2007.

At age 14, Sean Belnick was already making $1000 a month selling Pokemon cards and other collectibles on eBay. He figured that the same model could work with almost anything. And with a stepfather who worked for a furniture maker, that market seemed like the most logical place to start. Investing $600 in Web hosting and online advertising, he launched BizChair.com to sell office furniture direct to businesses. Now, six years later, Belnick occupies the number 2 spot on Inc. Magazine's list of America's "30 coolest young entrepreneurs," and his customer list includes Microsoft, Google, and the Pentagon.

Now a junior at Emory University in Atlanta, studying business (naturally), Belnick leaves the day-to-day operations to his stepdad, Gary Glazer. After graduation, he plans to climb behind the CEO's desk once more. And when he does, he'll be sitting on more than just his laurels.