Jokes and Films Are Fun, but He Loves His Banjo is a New York Times article by Dave Itzkoff about Steve Martin's new bluegrass album called "The Crow: New Songs for the Five-String Banjo".
From the article:
Among country and bluegrass musicians, Mr. Martin is regarded as a master of a difficult five-fingered playing style known as clawhammer or frailing, in which the instrument’s strings are pushed down by fingernails, rather than pulled up with picks.
“I know I can’t play it,” said Mr. Scruggs, for whom the traditional three-fingered Scruggs style is named. “So it’s a challenge for me.”
Martin is widely quoted as saying, "You just can't sing a depressing song when you're playing the banjo." You can find a young Martin jamming with the Muppets here.