Imagine, if you can, 75-year-old former Vice President Walter "Fritz" Mondale busting a move in the middle of a video arcade.

Now imagine an arcade game that actually gives you an aerobic workout and leaves much more than your thumbs throbbing. Sounds ridiculous, doesn't it?

But thanks to Dance Dance Revolution, known to its fanatical followers as DDR, the ridiculous has become reality.

"Walter Mondale was in here on one of the machines," said Erika Breske, marketing coordinator for GameWorks at Block E in downtown Minneapolis. "His son, Ted, was having a party here, and Walter tried DDR out. One of our managers got him up there and was dancing with him."

When Fritz has found his way onto a DDR machine, it's safe to say the feet-on dancing game is no longer just a passing fancy that first emerged in Japan in the late 1990s.

In fact, Dance Dance Revolution has become one of the most popular video games in the United States, spawning online communities at Web sites such as http://www.ddrfreak.com/ and dance parties around DDR machines in arcades, college dorm rooms and high-schoolers' basements all across the country.

"It's a thrill for me to get up and dance in front of a bunch of people," said Shawn Wolf, 24, after huffing through a three-song set on a DDR MAX 2 machine at GameWorks one recent weekend. "I used to come here and watch people dancing, and there are some guys who are pros, who can really do amazing things. That inspired me to practice at home so I could come out here and not embarrass myself."

Starting out in his basement, Wolf, a Minneapolis resident, spends several hours a week at home fine-tuning his moves on the Sony PlayStation version of the game. The home game ranges in price from $69.99 to $99.95, depending on the type of dance pad and number of songs that particular version comes with.

Wolf says after practicing, he'll go to GameWorks two or three times a week to strut his stuff on the arcade machines, which usually cost anywhere from 50 cents to $2.50 for three songs. If the crowds at Twin Cities arcades are any judges, Wolf is far from alone in his love for DDR.

With DDR, "It gets really loud in there on weekends," said Jim Vanderaarde, manager of Grand Slam USA arcade in Eagan. "Once somebody good gets going, a big crowd gathers. You can hear them stomping and cheering all the way out at the front desk."

Although big crowds come to watch and dance, DDR players like Wolf say sharing the machines isn't a problem. While some arcades use the method of placing tokens or quarters along slots attached to the machines to save a player's place in line, other places like GameWorks simply allow users to regulate themselves.

"It's pretty easy to figure out who's there to dance and who's there to watch," Wolf says. "There are usually a bunch of regulars who play all the time, and you just take turns. And if it's crowded, it's nice anyway to be able to take a break between songs."

While some patrons (especially first-timers or older gamers) step on without knowing all the steps to a song, Breske said most DDR players — the bulk of which range in age from 14 to 25 — come prepared.

"These kids have it at home, and they come here and already know the routines," she said. "They sometimes have two people standing next to each other, and they play off each other and literally jump over one another like a pair doing a dance routine."

A GAME THAT'S GOOD FOR YOU

The irony in all this, of course, is that DDR is the antithesis of a stereotypical video game. While most forms of electronic entertainment don't require players to exert much physical energy, DDR forces participants to be constantly moving, sometimes demanding hundreds of steps during a 90-second song as difficulty levels increase.

"We've actually got some girls who work here during the day and they'll do an hour on DDR after their shift is over," Breske said. "It's a real workout."

Minneapolis resident Frank Jackson, 19, got hooked on DDR when he first bought the PlayStation home version. Although he complained that the dance pads for the home version are too small for his feet, Jackson says he couldn't help but fall in love with the game.

"It has great songs," he said, relaxing after a session at GameWorks. "You really have to put a lot of energy into it."

While Jackson took a break on his machine, dance fans Larry Barthel, 30, and Jeremie Finck, 22, were busy watching Wolf stomp through his routine on an adjacent DDR game.

"He's 'DDR-in-training,' " Barthel said of his friend Finck, who hails from Nova Scotia, Canada.

"But they have these machines all over Canada now too," Finck said. "It's great exercise. I'm not any good at it right now, but I'm learning."

Barthel, of Minneapolis, said that while DDR obviously appeals to a younger generation of energetic gamers, older players still enjoy the game.

"It's something different," he said. "It's a unique genre, totally separate from a racing game or a sports game. It's almost like line dancing or something. I actually use it as an aerobic workout."

With everyone from Mondale to teenagers trying Dance Dance Revolution, Wolf doesn't see the game's popularity taking a breather anytime soon.

"It's too much fun," he said, stepping off the machine, sweat soaking his T-shirt. "It's great to have people watch you while you play a game, and I can come here and know I'll get a great workout that night."