Fountain of Youth: The Under 30 Hall of Fame
Bill Gates & Paul Allen, Microsoft
Allen convinced Gates to drop out of Harvard to officially start Microsoft in 1976. After developing an operating system called MS-DOS for IBM in 1980, Microsoft became a major player in the computer software industry. The company powers most of the world's computers today. After 13 years as the reigning world's richest man, Gates recently slipped to No. 3, with a net worth estimated at a mere $58 billion. Allen, who owns the Seattle Seahawks, comes in at No. 41 with $16 billion.