YOUNG ENTREPRENEURS

Ben Kaufman
Age: 20
Location: Burlington, Vt.
2006 Revenue: $1 million
Employees: 14
Year founded: 2005
What it does: Mophie makes cases, splitters, arms band, and clips for the iPod. The iPod accessory market may be crowded these days, but Kaufman's goal is to turn Mophie into a community-based product-development company that will solicit ideas for all kinds of new products -- not just iPod add-ons -- from a 50,000 member online user base. He's got $2 million in venture capital and a former top exec from Burton Snowboard on board to help him do it. Revenue is expected to hit $5 million this year.

Sean Belnick
Age: 20
Location: Kennesaw, Ga.
2006 Revenue: $24 million
Employees: 75
Year founded: 2001
What it does: At 14, Sean Belnick started a direct-shipping company for office furniture from his bedroom -- with $500. The company now stocks many of the products it sells in a new 327,000-square-foot warehouse in Canton, Ga., and has branched out into home furniture, medical equipment, and school furniture. Notable clients include the Pentagon, Microsoft, and "American Idol."

Bo Menkiti
Age: 30
Location: Washington, D.C.
2006 Revenue: $640,000
Employees: 10
Year founded: 2004
What it does: A Harvard MBA, Bo Menkiti sold his own home in the capital's Columbia Heights neighborhood to launch an urban real estate development, brokerage, and sales firm aimed at first-time buyers in the underserved middle market. In less than three years, his team has developed 33,000 square feet of residential and commercial property and brokered more than $60 million worth of real estate in the region. What's next for Menkiti? Developing a new 30-unit affordable housing building from the ground up.

Sam Altman
Age: 22
Location: Mountain View, Calif.
2006 Revenue: undisclosed
Employees: 30
Year founded: 2005
What it does: Loopt software provides location-based functions for cell phones, allowing users to see where their friends are on a map. The software also sends text alerts when friends come in close proximity to one another, and can search for nearby restaurants. It'll even tell you what spots your friends have tagged as favorites. Loopt's service is currently available on Boost Mobile, and is expected to launch on Sprint and other carriers within months. Altman says he wants to bring the Internet out of the home and into the wild. "The company's mission is to enhance, improve, and make more of real-world interaction," he says.

Katie Kerrigan
Age: 27
Location: Libertyville, Ill.
2006 Revenue: $57,000
Employees: 1 full-time, 2 part-time
Year founded: 2005
What it does: When Kerrigan, a former college athlete, entered the professional world, she was discouraged by the lack of stylish shoes for tall women. At six-feet tall with a size 11 shoe, she began looking for solutions. While getting her MBA, she drafted a business plan for a company that sold dress shoes to women with larger feet -- sizes 10 and above. In 2005, Kerrigan launched her website, KathrynKerrigan.com, where other women like herself can find everything from stylish high heels to trendy flats. Kerrigan works with a craftsman in Italy to create her original designs. Her shoes can be found in boutiques nationwide and in her new flagship store, which opened this year in Libertyville, Ill. Sales are expected to quadruple this year.

Byron Myers, Ali Perry, and Brenton Taylor
Ages: 27 (Myers), 25 (Perry), and 26 (Taylor)
Location: Goleta, Calif.
2006 Revenue: $15 million
Employees: 100
Year founded: 2001
What it does: Winning a business plan competition at the University of California Santa Barbara prompted these friends to take their idea for an oxygen concentrator and actually form a company. Perry's grandmother complained about the bulkiness and inconvenience of her old oxygen machine, so the trio designed their compact device to filter out the nitrogen from room air, eliminating the hassle of having oxygen tanks delivered. Inogen's machine can also be plugged in anywhere or used on the go with a rechargeable lithium ion battery. The company has sold more than 10,000 devices.

Raj Lahoti
Age: 25
Location: San Diego
2006 Revenue: $11.5 million
Employees: 15
Year founded: 2003
What it does: After a few years dabbling in Internet domain acquisition and traffic brokering, Raj Lahoti set out to build up one of his brother's domains in order to provide meaningful content in an area that, well, generally lacks it. DMV.ORG, the "Online Unofficial Guide to the DMV," aggregates information from the (often dreaded) Department of Motor Vehicles in each state -- all in one place. Users can access information on everything from applying for a license to ordering a driving record, without the aggravation of standing in the DMV's endless lines.

Geoff Cook, Dave Cook, Catherine Cook
Ages: 29 (Geoff), 19 (Dave), and 17 (Catherine)
Location: New Hope, Pa.
2006 Revenue: undisclosed
Employees: 25
Year founded: 2005
What it does: A social networking site for teens, myYearbook.com was hatched around the family dinner table by siblings Catherine and Dave two years ago. With older brother Geoff now on board, the site has since grown from a single high school to more than 3 million members and more than 4.5 million visitors a month, ranking it third among all social networking sites in the United States, behind MySpace and Facebook.