he'll be a hero to kids everywhere. Read a Q&A with Salman Khan. Watch Khan's TED talk on "flipping the classroom," as well as Khan Academy videos on calculus and the origins of the Earth.

Although the Grassroots Academy serves about 50 to 60 students between the ages of 8 and 18 year round, its impact has a far-reaching ripple effect. “We’ve worked with hundreds of kids over ...