Randy Pausch, the Carnegie Mellon University computer scientist whose last lecture, titled "Really Achieving Your Childhood Dreams," became a viral video on YouTube, died today at the age of 47 after a two-year battle with pancreatic cancer. Doctors told Pausch last August that his cancer, which was in remission, had recurred and that he would live only three to six months longer.

A month after hearing the dreadful news, on September 18, 2007, Pausch delivered the lecture that would become his legacy. He regaled students and colleagues with a tour that was both heart-wrenching and amusing of his attempts to live out his childhood fantasies. Some he managed to pull off: experiencing zero-gravity, helping to design attractions for Disney World by participating in its Imagineering program and writing an entry in the World Book encyclopedia--on virtual reality, his expertise. Others didn't come true, such as becoming a pro football player. He alluded to teaching as a way of helping students live out their dreams.

The video of his last class, which came to be known as "The Last Lecture" and surfaced on YouTube late-last year, has been viewed nearly 3.5 million times. The lecture became a best-selling book with the same title. 

"I'd like to thank the millions of people who have offered their love, prayers and support," Pausch's wife, Jai, said after his death. "Randy was so happy and proud that the lecture and book inspired parents to revisit their priorities, particularly their relationships with their children. The outpouring of cards and emails really sustained him."

But Pausch told his students that it was his children – Dylan, 6, Logan, 3, and Chloe, 2 – for whom the speech was really intended.

"I knew what I was doing that day," he wrote in the introduction to his book. "Under the ruse of giving an academic lecture, I was trying to put myself in a bottle that would one day wash up on the beach for my children."

Aside from his Internet fame, Pausch is best known as the creator of Alice, a program that allows children to create 3-D animations. Carnegie Mellon's president Jared Cohon said of Pausch, to CNN: "His love of teaching, his sense of fun and his brilliance came together in the Alice project, which teaches students computer programming while enabling them to do something fun -- making animated movies and games." IBM fellow Grady Booch praised Alice for the ease with which it teachers young people computer programming in an interview last month with our technology editor, Larry Greenemeier.

Pausch also cofounded Carnegie Mellon's Entertainment Technology Center, which according to its website, brings together technology specialists and artists to "produce artifacts that are intended to entertain, inform, inspire, or otherwise affect an audience/guest/player/participant."