The sign in the window says, "retro arcade and museum." Retro, because most of the arcade games inside this Lake Street storefront were considered cool 25 years ago. A museum, because in the age of Wii and PlayStation 3, these stand-up game cabinets are relics from another time.

This is Rusty Quarters, the only vintage arcade in the Twin Cities.

The small storefront, containing 21 old-school arcade games, is owned by Sage and Annie Spirtos, two proud geeks who have a mutual affection for collecting things (Sage likes toys, Annie likes Winnie-the-Pooh).

On a recent night, Sage was holding court behind his iMac inside the arcade. He wore a Donkey Kong T-shirt with the phrase "Going Bananas" splayed across his belly. A group of boys were jostling for position in front of a three-player game.

"Our biggest moneymaker is 'Rampage,'" he said of the 1986 game. "It's a no-brainer. You just go around smashing stuff."

If only life were that simple.

For the arcade's owners, this is their last chance. Sage and Annie opened a comic-book shop in this same south Minneapolis location in 2010. It didn't do well, so they tweaked the concept, turning it into a novelty toy shop (think Uglydolls and action figures). They called it Puff N' Stuff, but "people were confused and thought we were a smoke shop," Sage said.

While the colorful merchandise wasn't selling, a 30-year-old "Donkey Kong" arcade game in the corner was a hit. It got to the point that players would be standing outside waiting for the store to open.

So the couple ditched the stuffed animals and began scouring Craigslist and calling arcade dealers nationwide. In time, they amassed a respectable collection of vintage cabinet games. Since they opened Rusty Quarters in late December, the place has been packed most nights.

It's easy to see why. Each game costs one quarter. Huddled in front of the machines are thirty-somethings reliving their youth, hipsters on their way to the nearby Bryant-Lake Bowl and parents taking their children on a nostalgia trip.

On quarters alone, this business is surviving (and maybe thriving).

"We're doing pretty good," Sage said. "Not enough to be millionaires but enough to keep the lights on."

Big, bright arcades still exist. There's a Dave & Busters in Maple Grove, and the Mall of America just reopened an arcade-and-bowling combo called Sky Deck. But at those arcades, gamers blast monsters with replica assault rifles, they speed through virtual streets in race-car cockpits, they talk to the games and the games talk back. At Rusty Quarters, the game cabinets contain a joystick and a couple of buttons. One game, "Asteroids," is from 1979. The other classics are all here: "Frogger," "Joust," "Ms. Pac-Man."

Sage said he's interested in a few titles from the 1990s ("Teenage Mutant Ninja Turtles"), but most of that decade's games were lost to the junkyard, casualties of the arcade industry's collapse in the wake of the home-console boom.

A Kong-tastic player

Retro arcades like Rusty Quarters are rare, mainly because the games are hard to come by. Chicago has a similar arcade, New York is home to a couple (one with a bar).

"These machines have essentially been hunted to the point of extinction," said David Hansen, a Rusty Quarters regular.

Sage said Hansen, 30, is one of the best players he's seen at Rusty Quarters. The freelance writer holds the arcade's high score on "Donkey Kong" (557,000!).

Great "Donkey Kong" players are a breed apart. An acclaimed full-length documentary -- 2007's "The King of Kong: A Fistful of Quarters" -- documents a rivalry between two of the world's best. While its graphics are rudimentary by today's standards, the game-play is immensely difficult.

Another Rusty Quarters regular is Mitchell Elliott, 21, a Bethel University football player. At 6 feet 4 and 300 pounds, he dwarfs many of the machines. Elliott used to spend his free time searching the Twin Cities for the handful of "Donkey Kong" machines still available to the public. One is in a coin laundry, another at a bowling alley. Most of them showed a high score by a player with the initials "GED." He wanted to meet this person, someone who was as good as he was.

Last year, he walked up to the "Donkey Kong" machine at Sage and Annie's toy store. "GED" was playing. It was Hansen.

"I just wanted to hear his story," Elliott said. "Maybe we could learn something from each other."

The two now hang out often at Rusty Quarters.

"At one point I realized all my hobbies were just ... me ... doing stuff alone," Elliott said. "So I thought I should go out and be with people."

The true nature of the game

Hansen finds something poetic about mastering these machines, especially "Donkey Kong."

"I find the graphics to be really beautiful and engaging," he said. "They conceal the true nature of the game. It's tremendously cerebral. People who have played it for 25 years still discover new elements they never saw before. I often wonder, did its makers know they were building a game that was bottomless?"

Hansen is very protective of the two "Donkey Kong" machines at Rusty Quarters. "I get really nervous when I see some 5-year-old with a bottle of Coke in hand, mashing on the buttons," he half-joked.

Sage says he does his best to keep these antiques in pristine condition, but that means performing daily maintenance. Coin slots get jammed. "Frogger" has a bad capacitor.

"'Q*bert' has blown a fuse," he said last week. "I have to go to Radio Shack."

Day after day, Sage and his wife are making a business out of this museum of old sensations, one quarter at a time.