Britain's Queen Mum, bouncing back from a recent stay in the hospital, is still working the crowds at 101.
Jazz great Lionel Hampton was still performing last year at 92 (he turned 93 in April).
Is it something in their genes? Something they ate? The power of positive thinking?
What keeps these and a growing number of elders going as they near and pass the century mark may be just the right combination of those elements and more.
Researchers who are working to unlock the keys to long life say the definition of old age is changing. And as more older people live longer, active lives, they are helping to create new attitudes about aging.
"We are definitely redefining the way people age, as we are redefining the expected length of life," said Robert Kahn, a University of Michigan psychologist and co-author with Dr. John Rowe of the 1998 book "Successful Aging."
"Those of us who live now are the beneficiaries of great gains in medical knowledge, in public health and sanitation," Kahn said. "And along with those changes come changes in the way people see and think about old age, and how older people are expected to look, dress, act."
Last year, the National Council on the Aging conducted a poll of 3,048 Americans age 18 and older. A total of 44 percent of the survey respondents age 65 and older said senior citizenship has proved to be the best time of their lives. And 84 percent of survey participants of all ages said they would be happy if they live to age 90.
Asked to define old age, only 14 percent of the people surveyed cited a specific number of years. More said they would define old age as a decline in physical ability or mental functioning.
"We've entered a new age of old age," said James Firman, president of the National Council on the Aging.
While older people were showing more optimism, younger people in the survey seemed to overstate some of the problems of old age. A total of 54 percent of those under age 65 believed insufficient amounts of money to be a very serious problem for older people; but only 12 percent of those over 65 thought lack of money was a problem for them personally. Among the younger set, 38 percent assumed older people must be terribly lonely, but only 4 percent of the senior citizens said loneliness was a very serious problem for them.
When it comes to their love lives, it seems that older people are doing all right.
About half of all Americans age 60 and older are sexually active, according to a 1998 survey by the National Council on the Aging. Most of those who are sexually active - 74 percent of men and 70 percent of women - say they are as satisfied or more satisfied with their sex lives than they were in their 40s.
What's normal aging? That depends on the definition of normal.
"Let's begin with normal as average, what most people do," Kahn said. "In our prosperous, overfed, under-exercised country, most people gain weight as they age. And most people show increases in blood pressure and blood lipids - cholesterol and triglycerides - and in blood sugar. All of these are risk factors for cardiovascular disease and/or diabetes."
But these changes aren't inevitable.
"We know that because not all people show these risky characteristics as they age, diet, exercise and genetic factors seem to explain the difference," Kahn said. In his book, Kahn emphasizes that it is never too late to start exercising or make other health changes that can transform lives.
Kahn said all people do show some losses as they age: in muscle mass, in the ability to heal rapidly, in the tendency toward gray hair.
Who wants to be 100?
Centenarians are the fastest-growing segment of the population, according to Dr. Thomas Perls, assistant professor of medicine at Harvard Medical School and director of the New England Centenarian Study.
The Census Bureau estimates that by 2050, when baby boomers will be reaching the century mark, the population of centenarians could reach more than 1 million nationwide. But does anyone really want to live to be that old?
Many people say they fear living to an advanced age because they worry about dramatic losses in mental capacity, such as those brought on by Alzheimer's. The percentage of people afflicted with Alzheimer's and related disorders increases with age.
But several studies have shown that people who remain actively engaged in learning as they age may be protected from certain types of dementia.
"The evidence says no, not everyone becomes demented in old age," Kahn said. "Some losses in short-term memory and some losses in rapidity of response do seem inevitable, but these are not dementias and they are not Alzheimer's disease."
In 1999, using data gathered from the New England Centenarian Study that began in 1993, Perls and Margery Silver, associate director of the study, published "Living to 100: Lessons in Living to Your Maximum Potential at Any Age."
The study showed that rather than surviving disease, many of the oldest of the old simply avoid it. Perls said that the notion that advancing age brings increasing sickness needs to be replaced, at least when the subject is 100-year-olds.
"Instead of 'the older you get, the sicker you get,' it should be 'the older you get, the healthier you've been,"' he said. "People who make it to 100 don't become incapacitated until the very end. They are living 90 to 95 percent of their lives in terrific health."
So how do they do it?
Centenarians are rarely smokers, nor are they often obese, although following one particular type of diet doesn't seem to be a factor, Perls said. And they manage stress well.
"They don't dwell on things," he said. "They are able to let go."