When Slap Shot was released on Feb. 25, 1977, it was a middling success.

Despite mostly negative reviews that tended to focus on what they saw as the film's glorification of violence, it eventually went on to earn $28 million at the box office against a $6 million budget. In the following decades, its popularity exploded as it became a textbook example of what makes a cult-classic movie.

The film was conceived of by screenwriter Nancy Dowd, whose brother Ned was playing for the Johnstown Jets minor-league hockey team in Pennsylvania. Her access to this world gave the film an immediate feeling of authenticity. She had him carry a tape recorder when he was around his teammates so she could get the feel of the way they talked. She used several real-life minor-league hockey events – from fights that took place before the game started to players going into the stands to fight fans – to spice up the screenplay.

Director George Roy Hill cast Ned in the film (as one of the main antagonists), along with several of his hockey teammates, all of which gives the proceedings a sense of realism that shines through the comedy.

Watch the 'Slap Shot' Trailer

The movie's plot is centered on Reggie Dunlop (Paul Newman), an aging player and coach of the Chiefs, a minor-league hockey team in the fictional town of Charlestown in New England. When Dunlop gets news that the town's steel mill is going to close, he knows that the resulting economic devastation is going to force the team to be sold, ending his career and that of many of his players. In a desperate attempt to prop up the popularity of the team, he starts giving playing time to the notorious Hanson brothers (played by actual minor-leaguers) who wrap their knuckles with tinfoil before every game to give them an edge in the fights they inevitably start.

This new, violent style of hockey disgusts the Chiefs' best player, Ned Braden (Michael Ontkean), but it delights the fans, and the team's popularity surges. Things change when Dunlop finds out that the owner plans on folding the team anyway, despite this newfound popularity, to take the tax write-off. Suffering a crisis of conscience, Dunlop decides to go back to trying to win by skill instead of fisticuffs, only to realize that the Chiefs' main rival, Syracuse, has brought in a bunch of fighting goons for the championship game, including the notorious Ogie Ogilthorpe, played by Ned Dowd.

Predictably, the final game descends into an all-out brawl. Revolted by this, Braden decides to derail the fight by doing a striptease on the ice, in one of the most famous scenes in sports-movie history. Outraged, the Syracuse captain gets into a fight with the referee, which results in Syracuse getting disqualified. The Chiefs win the championship.

Watch Striptease Scene From 'Slap Shot'

Like virtually every cult-classic movie, Slap Shot abounds with great lines. Some of these are bawdy, like Steve Hanson's expletive-laden reminder to a referee that he's trying to listen to the national anthem. Others are sly, like an opposing team's radio announcer (Paul Dooley) telling his listeners during a brawl that if only he could, he, too, would be fighting the marauding Chiefs players.

Quote one of these lines to a fan of the film, and they'll come right back at you with two more; it's exactly this kind of endlessly repeatable dialogue that enables some movies to outlast their original moments and become beloved by later generations of viewers.

The second element of the film's cult success is the fact that it has great characters, embodied by talented performances. Newman was at the moment in his career when he would increasingly shift from playing young heartthrobs to playing aging curmudgeons. His down-and-out character here anticipates his later roles in classics like The Verdict or The Color of Money, but with a comedic turn that was always an underrated part of his abilities.

The rest of the cast rises to the occasion as well, including the hockey players - a tribute to Hill's ability to work with actors, even amateur ones. Every character manages to feel both slightly outrageous and somehow true-to-life, which, like the great dialogue, allows the film to bear repeated watching, an essential element of cult-movie success.

Watch the Hanson Brothers in 'Slap Shot'

Plus, the film convincingly sells its setting. The world of minor-league hockey and the gritty, blue-collar existence that characterized so much life in the '70s are both incredibly well-realized. The comedic action and zany characters are foregrounded against real-life struggle. The people in the film are surrounded by economic devastation, and many of them have no life options outside of hockey.

Yet at the same time, they're not pessimistic about their situation. Mostly, they just want to drink some beer and play their sport. This makes the world of the film feel fully realized, a place that one can dip into again and again, and find oneself immersed.

All of this has allowed Slap Shot to reach massive stature among a certain strand of movie fans, and it often places high on lists of best cult movies. Not bad for a film that started with a screenwriter chronicling her brother's minor-league hockey experiences.

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