40 Under 40: When they were kids

Now, they're the best and the brightest young minds in business. Back then, they were precocious toddlers and smiling babies. Can you guess who's who?

Hint: As a frustrated and underfunded public school teacher in 2000, the charity superstar launched an outfit that has sponsored more than 200,000 classroom projects and raised nearly $100 million. He originally thought he'd be a cop (the New York police academy held a spot for him for years), but now he has a new goal -- making school budgets smarter by opening up his charity's wealth of data. Stephen Colbert (a board member) recently sang a rendition of Rebecca Black's "Friday" as part of a stunt to raise money for the cause.

By Anne VanderMey, reporter - Last updated October 24 2011: 2:34 PM ET
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They're the hottest young stars in business across the globe. They're innovators, disrupters, and job creators; in fact, it's a pretty safe bet you're going to be working for them someday -- if you aren't already!