The rules of Toothless Tuesday seemed simple enough: Anyone with a missing tooth got a free beer. But not just one tooth, since P Moss, owner of the Double Down Saloon, discovered that it didn’t rule out much of his clientele. Even when he upped it to two teeth, he was still giving away beer like water. So it came to be that you had to have two missing teeth in a row.

Some years ago, Moss had explained the rules to a disappointed man with only one missing tooth when another patron offered to pull a second tooth out. He accepted the offer. “What could I do?” Moss recalls. “I gave him a pair of pliers, and he yanks and yanks and yanks and yanks, and the guy’s screaming. Oh, it was horrible.”

At last, the tooth relented. “He looks up at me and smiles this big, bloody grin and says, ‘Gimme my beer!’ And I said, ‘I told you; it has to be two teeth in a row.’ The guy pulled the wrong tooth!”

Moss watched the furious, blood-soaked patron get his vengeance, chasing his makeshift dentist out the door and around the corner. But he never did get his beer. “Hell no, I didn’t give it to him!” Moss says. “The rules are the rules.”

Toothless Tuesday is now a thing of the past, but little else has changed since the bar’s early days. The drinks are still cheap. The shows are still free. The grotesque bathroom still evokes Trainspotting’s infamous toilet scene. Behind the bar, handmade signs still offer the original Bacon Martini and happy-hour specials like the Graveyard Trifecta—a PBR, a Slim Jim and a shot of the fabled Ass Juice—for $4. And the jukebox remains a garage-punk haven, providing the nightly soundtrack for the mohawked punks, mustached truck drivers, college students and thickly accented tourists who make up the Double Down’s historically sundry crowd.

In a town where trendy, million-dollar nightclubs are considered lucky to last a year, all that might explain how the little joint on Paradise has come to celebrate its 20th anniversary this weekend, with four dedicated nights of its typical brand of debauchery.

“You have to decide what you’re going to be and stick to it. I didn’t build this place to be the next big hot spot for a year,” Moss says.

Even so, the Double Down has become a hot spot in its own right. The bar’s eccentricities have earned it landmark status that draws as many tourists as locals, including food and travel aficionado Anthony Bourdain, who recently ranked the Double Down among his top five bars in the world. Publications like Playboy and Rolling Stone have also deigned it among the best, and its reputation has spread so far that, in 2006, Moss opened a second location in New York.

Looking around the Double Down now, with its DIY wallpaper of stickers, posters and murals, it’s hard to imagine the joint as it was when Moss walked in as a prospective buyer two decades ago: a room with sterile white walls and mirrors to help compensate for its small size. The real estate agents followed him in reluctantly, apologizing for the space and location. One look around and Moss decided it was perfect.

“It was a white elephant; nobody wanted it,” he recalls. “I thought, the whole Strip is three blocks away, how in the world is this a bad location? I couldn’t understand how no one saw it.”

Moss saw a place that could break from the monotony of other dives at the time, one that showed music videos and indie cartoons on TV instead of ESPN, that had artists like Iggy Pop on its jukebox rather than Journey, and, above all, a place where everyone—from blue-collar workers to musicians to college students—could comfortably share space at the bar at the end of the day.

“I wanted to start a bar that I myself would want to drink in,” he says, explaining that while bars like the Huntridge Tavern, Champagnes Cafe and the now-defunct Cooler Lounge were frequented by an alternative crowd, they nonetheless lacked a sense of belonging. “They’d hang out at those bars, but the place itself wasn’t theirs. It wasn’t what they wanted it to be.”

“When I bought the bar, I decided the most important part of that location would be a jukebox that would draw people in, that would give the place character,” Moss says of his decision, unprecedented here at the time, to feature a jukebox that catered to punk rock and its offshoots.

But while music might have been a selling point, Moss initially wanted nothing to do with live shows, worrying they would alienate patrons looking to kick back at a bar. The Double Down’s signature, nightly free live shows actually came about accidentally, when the ’90s band Man or Astro-man? discovered the Vegas venue they had booked had been gutted. A friend called Moss, pleading to let them use the Double Down.

“I said no, but after three more calls I finally gave in, and two hours after that I had 300 people,” he says. “So, it started with me being wrong.”

Rob Ruckus, a longtime Double Down bartender and fixture in the local punk scene, was in the first band ever to play the venue, Godboy, which opened for Man or Astro-man? that night. “At first it was just an old-man-drinking-whiskey-during-the-day-to-forget-his-life kind of bar,” he says. “[But] we sold that bar out of every drop of booze they had and even had to go to the store across the street and bring in more. After [Moss] saw how cool the music scene could be in Las Vegas, he jumped in with both feet.”

In those days, Vegas music venues came and went, and booking was inconsistent at best. The Double Down stage began providing local and touring punk and alternative acts—from name bands like the Adolescents, T.S.O.L. and NOFX to Vegas mainstays like Thee Swank Bastards, Blue Man Group side project Überschall and The Vermin (with whom Ruckus has played bass for 18 years)—a consistent place to play.

“The Double Down has done more for bands in this town than anyone,” Ruckus says. “A lot of bands got their start there; a lot of touring bands made much-needed food and gas money there; a lot of bands had to raise their game to play there, because if you suck, the crowd will let you know it.”

Ultimately, the popularity of the Double Down’s live shows enabled the venue to become the point of community Moss originally envisioned.

For Jenn O. Cide, a local performer and sound engineer who hosts the bar’s monthly Punk Rock Bingo event, the Double Down has served as both a social and musical refuge. She played her first show there at 14 with a fake ID on New Year’s Eve 1992 and started doing sound shortly thereafter.

“The Double Down gave people a place not just to hang out, but they could go there and perform on the same stage as their heroes,” she says. “For the alternative community, it was just a place you could go and not get a dirty look. Musically, and for community, it was common ground. The Double Down helped make it okay to be weird.”

Twenty years on, Moss intends to keep it weird. He’s fielded numerous offers to buy and franchise the Double Down, with the largest—from a “tabloid celebrity” Moss declines to name—coming in at $1 million.

“I believe in the big picture. I believe in doing things over the long haul,” he says. “So to cash out and take money for that would pretty much go against everything I believed in from the start with this.”

Follow Andrea Domanick on Twitter at @AndreaDomanick and fan her on Facebook at Facebook.com/AndreaDomanick.