40 years of "A Prairie Home Companion": Behind Garrison Keillor's success

Part sketch comedy, part storytelling, part music, "A Prairie Home Companion" is a homespun, wholesome variety show that's now in its 40th year. Each Saturday night, about 4 million listeners tune in on the radio.

It all comes from the ever-churning mind of Minnesota's favorite son, Garrison Keillor, reports CBS News contributor Jamie Wax.

"People love to be spoken to," Keillor said. "The basis of friendship, I think, is the voice of one other person carrying on a conversation with you."

Fred Newman is the show's human sound effects machine.

"[Keillor] is a writer, more than anything, and he's a brilliant observer," Newman said.

Every show is performed on stage in front of a live audience.

"It's the social pressure of standing up in front of people and you look at all these, you know, 10-, 11-, 12-year-old kids there. You've got to do something for them," Keillor said. "If necessary, you may have to talk about flatulence. There may be no alternative, you know?"

Keillor said great ideas can come from "stupid, good luck," but he is driven by his never-ending desire to be better.

"The best you can hope for really is, when you are young, people instill in you an ambition, a standard that you can never achieve. And you spend your life trying to roll the boulder up the hill," Keillor said.

The 71-year-old has rolled boulders up many hills. In addition to the radio show, he's authored 28 books. His latest, "The Keillor Reader," is a collection of his writings across many genres.

In one of the pieces in the book, Keillor said he lives under a towering sense of inferiority -- something he said is not self-deprecation for entertainment value.

"I think it's baked into you when you grow up in a small town in the Midwest. I have a very realistic sense of my own skills, and my main skill is editing," he said.

It's an important skill for a writer.

"Writing is rewriting. That's my principle," he said.

Keillor started writing as a sportswriter in Anoka, Minn., when he was 13 years old. He said the experience changed everything.

"There on the back page was your story with your name on it. And you never got over that."

When asked if he has a favorite moment in time, Keillor referenced his show.

"My favorite moment is 5 o'clock Central Time on a Saturday, and all of the work is now done. ... And the piano plays, and I sing the theme song, 'Hear that old piano from down the avenue.' And you've got two hours and you're free."

As for the future, Keillor said he will continue "A Prairie Home Companion" for at least a few more years. He's also working on a play and wants to write essays and columns rather than fiction.