Dorothy Peterson is more than a grandmother in her 80s; she's a cold-blooded table-tennis assassin. And she's got the trophy case to prove it. Each year, this Serena Williams of the 85-and-up set treks to the Huntsman World Senior Games in Utah and returns home to North Mankato, Minn., with a suitcase full of gold medals.

Peterson's age and dominance have left her with one problem, though: She can't find worthy opponents. After she laid waste to the competition at the 2008 games, The Mankato Free Press wrote about her fruitless search for decent competitors. The Associated Press picked up the story, and Peterson became national news. Then a contender stepped forward—a 77-year-old man with his own talk show.

He challenged Peterson to an on-air match, and that's how Peterson ended up playing Regis Philbin during an episode of Live with Regis and Kelly.

Regis may be the hardest-working man in television, but he couldn't fend off Peterson's forehand. The affable host quickly learned what her opponents already knew: Peterson's wrists may be well into their ninth decade, but they can still generate some vicious spin. By the time the ball stopped bouncing, Peterson had thrashed Regis, 15-6.

These days, Peterson uses her newfound fame to promote an active lifestyle for senior citizens. She closes each interview by reminding her fellow seniors, "If I can do it, you can do it. Age is just a number." As for her search for competitors, let's just say that the 2009 World Senior Games had a big increase in turn-out for women over 85. Peterson welcomed her new challengers by dominating the women's singles, women's doubles, and mixed doubles competitions. You didn't think the champ would go easy on the new meat, did you?

This article was written by Ethan Trex and originally appeared as part of our May-June 2010 cover story, "The United States of Amazing." We'll be excerpting stories from that piece throughout the day.

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