33-year-old Salman Khan recently quit his highly lucrative job at a hedge fund to devote himself to teaching students around the world for free. All without leaving his home.

Salman has created over 1,400 videos on YouTube -- covering everything from basic algebra to differential equations, physics, history, and finance. His videos attract more hits than most university websites. And comments, feedback, and notes of gratitude pouring in from youth around the world indicate these videos are both invaluable and very needed, in an education system that is not working for all.