Acting Their Age
According to David J. Ekerdt, director of the Gerontology Center at the University of Kansas, who coined the term busy ethic in a 1986 paper, there is an expectation that old age should be filled with activity. "Contemplation and inactivity is highly suspect all through life," he said.

Dr. Ekerdt said that when he used to interview retired couples for his research, "The wives would express dismay about their husbands, saying 'He just sits around and reads all day.' " That would hardly seem to be a common complaint now.

Take Jagger and Richards for instance. The Rolling Stones announced plans last week for another world tour. Mick Jagger will be 62 when the tour begins in August, and Keith turns 62 in December. While they may be aging rockers, they are also something else: active seniors.

But it's not just money that drives Mr. Jagger and Mr. Richards - and Charlie Watts, 63, and Ron Wood, the baby of the group at 57 - to keep performing.

"That's what they know how to do," said Nancy Morrow-Howell, a professor of social work at Washington University in St. Louis. "They're going to continue to do it."

So put your iPod earbuds in and crank up "Satisfaction".

Let's hear it for all those 60+ teenagers who know how to do it.