My father died when I was just out of high school, and it's fair to say that many of the qualities I value most in myself came from him. I admired his kindness and sense of humor and ability to walk into a room and instantly make friends. He had a tough life and never really found a job that suited his talents. But he was never bitter, he never complained. He was the man I someday still hope to be, and the biggest inspiration in my life.

And yet despite all of that, the passage of years has dulled his memory in my mind. I can't seem to imagine his voice, and pictures don't do much to fill in the increasingly large gaps in my memory. He's slowly fading from my life, and the thought of that scares me more than I care to admit.

What would you do if you knew you only had six months left to live?

I have a young son, and I sometimes worry that I'll suddenly disappear from his life. If I died in six months, would he remember me? Would he realize how much I loved him, would he somehow absorb some of the life lessons I want to pass on to him?

And then there's my wife, who I love more every day. The thought of being without her, of not being there by her side every day is staggering to me. I can't imagine how I would handle the news that I only had a short time left to live.

What would you do if you knew you only had six months left to live? What would you say if you knew you were going to die and had a chance to sum up everything that was most important to you?

Just about every person wrestles with these questions, which may be why a video called "The Last Lecture" has captivated the more than ten million people who have viewed it online since it was posted last year. The speech was given by Randy Pausch, a charismatic young professor of computer science at Carnegie Mellon University. The presentation was an annual event, typically given around some central question. Pausch learned about a month before the speech that he had pancreatic cancer, and only about six months left to live.

The 47-year-old father of three small children decided to make that speech his chance to impart every thing he felt he had learned about life. Partly for his friends and students, but also as a way of connecting with his children after he had passed away. He called the lecture his "message in a bottle" to his children, and he said he hoped that presentation--along with private videos he's making for them--will help give his children a sense of how much he loved them.

The lecture hall was jammed with friends and coworkers, many of whom had flown in from across the country to hear the presentation. Almost as an afterthought, it was recorded and posted online for people who were unable to attend in person. That video became a phenomenon, and led to a book deal for Pausch.

ABC takes an hour of its primetime schedule to revisit the story tonight in "The Last Lecture: A Love Story for Your Life." Diane Sawyer conducted three interviews with Pausch over the past several months, and it is an hour of television that is both uplifting and profoundly sad.

Pausch is a man who loves life and doesn't want to leave his family. But as he tells Sawyer, he came to realize there are some things you just can't change. Pausch speaks of how he is now trying to create memories for his three kids, Dylan, 6, Logan, 3, and Chloe, 18 months, and why he can't allow himself to wallow in self pity.

"I mean, the metaphor I've used is … somebody's going to push my family off a cliff pretty soon, and I won't be there to catch them. And that breaks my heart. But I have some time to sew some nets to cushion the fall. So, I can curl up in a ball and cry, or I can get to work on the nets."

His lecture and subsequent public appearances have inspired thousands of people, and the ABC special highlights a few of them. Some of the life changes are small, such as a father allowing a daughter who loves to draw to do so on her bedroom wall. Some of the life changes are more substantial. After battling breast cancer, Kaje Lane of Los Angeles told Sawyer Pausch had inspired her to pursue singing -- a passion she had put aside for many years.

"I think so many people relate to Randy because every one of us has some sort of dream they want to make real, or some sort of passion that they want to tap into if they're not already thinking that way. … I think people are just drawn to that. It's very magnetic to see someone positive not just about the big things but the little things."

For all of the acclaim, the sad reality is that Pausch is still likely to die soon, and he tells Sawyer that he understands that's the case. "Yeah, I'm not going to beat the cancer. I tried really hard … but sometimes you're just not going to beat the thing…I wanted to walk off the stage and say anything I thought was important, I had my hour."

As for myself, I try and create memories for my wife and son every day. I work to leave a legacy of my love and my best qualities. As Pausch has shown us, in the end, that's the best gift any of us can leave for our loved ones.

"The Last Lecture: A Love Story for Your Life" premieres on ABC on Wednesday, April 9th, 2008.