Katz worked as an analyst on Wall Street before following in his father's entrepreneurial footsteps to start customInk.com in March 2000. Customers can design their own hats, T-shirts, pens, and other merchandise online. The company was recently named one of the best places to work in D.C. by Washingtonian magazine and has a customer satisfaction rating of 98.9%.

Age: 29
Location: Tysons Corner, Va.
Revenue: $23.5 million
Employees: 110