Salman Khan and Shantanu Sinha ’98, MNG ’99, met as opponents in a high-school math competition in Louisiana in 1992. Both first-generation Indian-Americans who coded for fun in their spare time, they immediately hit it off. There was one problem in their budding friendship, as Khan saw it. “Shantanu was a math class ahead of me,” he recalls. “So I took every course I could to try and beat him.” Their love of learning, and friendly competition, helped both get into MIT, where they were freshman roommates at Next House.

Between them, Khan and Sinha pulled in seven MIT degrees (Sinha earned three SBs, Khan two, plus an MBA from Harvard). They woke up early to walk across the Charles, even in extreme weather, to tutor fourth through seventh graders at a Brookline public school. At MIT, both met the women they would marry (both of whom became MDs). Then they worked at tech startups and pursued lucrative careers—Khan at the hedge fund Wohl Capital Management, Sinha at the management consulting firm McKinsey. The pair are overachievers, perhaps even by MIT standards.

“If you’re lucky, you find a friend to inspire you,” says Sinha. Now the two friends, both 35, are trying to use technology to reach and inspire the unlucky kids through an educational nonprofit called the Khan Academy. They’ve created a set of free online teaching tools featuring a library of more than 3,200 (and counting) educational videos, most of them made by the charismatic Khan. The Khan Academy YouTube channel has more than 360,000 subscribers, and its videos have been viewed more than 167 million times.

Some revolutionary tech startups come from hackers in garages; the Khan Academy was born in a closet, where Khan went to record math videos. While working as an analyst, he started tutoring a 12-year-old cousin by phone at night after she bombed unit conversions on a math placement test. Soon she was ahead of her class, and Khan found himself helping more cousins. Although he liked tutoring, he got tired of repeating himself, so he started making videos and posting them to a public YouTube channel. Before long, they became popular with thousands of complete strangers. “He’s smart and hilarious, with a very natural personality, and that comes across in the videos,” says Sinha. Not long after Khan left the world of finance to work full time for his educational nonprofit, Sinha joined him with little hesitation, signing on as president and chief operating officer.

On a hot June day at Khan Academy’s headquarters in Mountain View, California, a week after delivering MIT’s commencement address, Khan is hard at work, oblivious to the allure of a foosball table that gives the place the feel of a Silicon Valley startup. Between making a set of videos about Stokes’s theorem (an important idea in vector calculus) and planning a summer camp, he stops briefly to talk about his vision. Khan believes that many students have been left behind by what he calls the “factory-like” traditional educational system. He hopes the Khan Academy can help motivate the demotivated, and pull those students up.

Khan admits that his habit of thinking big—on a worldwide scale—may amount to “delusional optimism.” When talking, he makes sweeping gestures that nearly pull him out of his chair and onto his Reebok-clad feet. This is the visual analogue of the enthusiasm that’s audible in his faceless videos, whether he’s rhapsodizing about the beauty of algebra or explaining venture capital.

When he built on the popularity of his online videos to found the Khan Academy in 2006, he says, “I didn’t even think we’d be used in classrooms.” Yet Khan is not shy about his ambition—that much is clear when he explains the “epic thought process” underlying his unconventional choice to make his products free. “This is an opportunity to leave something beyond me,” he says. “Nobody owns MIT or Stanford.”

Khan wants his academy to be not just an online resource but a major academic institution. “As an institution, you are helping define the discussion,” he says. “We want to redefine what is the ultimate classroom experience.” His idea of the ultimate experience is one offering all students materials that meet them at their own level, whether they’re at a private school in California or in an Indian village with no school at all. “We have the audacity to go straight to the student and cater to what they need,” says Khan.

The scale of that vision, and the business experience of the people running the company, have helped attract major donors including Google, the Gates Foundation, and the O’Sullivan Foundation. And Khan and his coworkers, who now number 30, are starting to see anecdotal but promising results. While an estimated 15,000 classrooms are tapping into its math curriculum on their own, the academy is working directly with 25 schools in the San Francisco Bay Area to incorporate its problem sets and other math materials (all of which are free), and to get feedback to make them better for students and teachers.

At Oakland Unity High, a charter school serving the city’s poor neighborhoods, teachers have seen major changes in students who use the Khan Academy math materials. For the past two years, incoming freshmen who had passed algebra in the previous school year scored an average of 17 percent on an algebra test. Many students don’t understand negative numbers or fractions but think they do, says teacher Kallie Berg; so if she lectures on those concepts, the kids tune out.

Using the Khan videos and supplemental materials helps Oakland Unity teachers get those students to tune back in. The problem sets—which are not multiple choice—confront students with what they don’t know and won’t let them move on until they answer a particular type of problem correctly, over and over again. “This forces kids to take responsibility for their learning,” says Berg. Teachers can watch their students’ progress—how long they spend on each problem, how many answers they get right, which concepts they’re struggling with—and set goals for each student. “It creates more accountability, which makes me more effective,” says Berg.

Khan Academy videos covering other subjects—including the arts, history, and biology—have already been introduced. So far they don’t have accompanying exercises, but a group of programmers at headquarters is working on it.

Next, Khan and Sinha will take on computer science, their second love after math. “Computer science is not taught in K–12—or it is not taught in a way that gives you the joy of the creative process,” says Sinha. They’re developing exercises that will teach students to write JavaScript code by providing instant feedback.

As usual, Khan is tackling the project with a combination of intuition and engineering, fueled by a simple joy in learning that was fostered at MIT. In his commencement address, he compared MIT to Hogwarts, the wizarding school in the Harry Potter series. “The science and innovation that occurs here looks no different than pure magic to most of the world,” he said. Expanding on that thought later at Khan Academy headquarters, he adds, “At MIT you have faculty members who have done things you think normal humans can’t do”—things like helping discover the quark. Khan is now trying to share with the world what he learned at MIT: that with the right kind of support, normal humans can and do accomplish amazing things. “Understanding the world and pushing it forward—that’s the real magic,” he says.