Genre Turning Point

While a Wham! Episode can change a single series forever... sometimes, something comes out that forever alters an entire genre. It wasn't the first entry into the genre, nor was it the last, but things were never the same after it came out. This often—but far from exclusively—happens with particularly notable Deconstructions; for example, superhero comics after Watchmen. If it does happen with a Deconstruction, it generally results in years' worth of both Darker and Edgier (and possibly Contemplate Our Navels) series in imitation... and Reconstruction series in response.

However, it doesn't always have to be a Deconstruction. Some shows, such as Sailor Moon, can radically redefine a genre without taking it apart.

Compare Wham! Episode, From Clones to Genre, Follow the Leader. Good chance of being a Trope Maker or Trope Codifier.

Anime

 * The Harem Genre was invented by Urusei Yatsura, but was re-invented in The Nineties by Love Hina, which set new rules for the genre: namely, an Unlucky Everydude male protagonist who lives with a bunch of girls (the violent Tsundere, the Bottle Fairy, The Ojou with the Hime Cut, the Shrinking Violet and the Exotic Foreign Girl) who all fall in love with him simply because he's a nice and sensitive guy, with the gaps in the plot smoothed over with dollops of fanservice. Almost every harem series since has followed its lead. Haters of this cannot forgive Ken Akamatsu.
 * Akamatsu can rest easy knowing that actual credit for re-inventing the genre goes to Tenchi Muyo! which refined and popularized the "harem anime" formula a full six years earlier. Love Hina was one of the first to apply the formula to a pure comedy with no fantastic elements, though.
 * It was NOT okay for men to cry in anime before Fist of the North Star. Afterwards, however, tears became a symbol of honorable masculinity tempered by a kind and gentle heart.
 * The original Mobile Suit Gundam basically revamped Humongous Mecha genre, single-handedly invented most Real Robot plot devices, and, along the way, ushered the Otaku subculture into existence (though to be fair, other shows helped it in the latter).
 * Digimon Tamers marked the shift from fantasy to sci-fi in the Digimon series.
 * Yami to Boushi to Hon no Tabibito and Kannazuki no Miko showed that Yuri anime could be profitable; Simoun showed that it could be True Art.
 * Akira. Before it came out, it was distressingly common to see anime films and shows targeted toward older audiences horribly Macekred so they could fit into the Animation Age Ghetto. After it came out, people in the West finally got the idea that anime movies didn't have to be targeted towards kids at all.
 * Ironically, Akira was released by Macek's Streamline Pictures studio.

Comic Books

 * An example that isn't actually a "work." The outrage caused by the book Seduction of the Innocent led to the creation of the Comics Code. This killed horror and crime comics, then among the biggest hits for the industry, while saving the superhero genre, which was sinking at the time. This also led Marvel Comics to give Stan Lee and Jack Kirby the green light to experiment, as they were hurting in the wake of this turn in the medium. (Which in turn led to the Silver Age.) All of this led to the terms "comic book character" and "superhero" being almost interchangeable in the North American market.
 * The Silver Age changed superhero comics forever. It introduced more flawed and relatable characters, more sophisticated themes, and more complicated plots. This lead to an eventual shift in the target audience for comics from children to late teens/young adults.
 * Spider-Man broke the mold as a teen superhero who was not a sidekick and had no mentor or guide, so that the first thing he thinks to do with his powers is make money. (Okay, so Plastic Man started out as a thief, but Spider-Man still had a huge impact on the genre.) Also introduced the idea that the superhero with a chaotic personal life, at least in part due to the fact that they're a superhero (the Secret Identity, for example, which causes the hero trouble as he has to think of a way to explain his inability to be in two places at once).
 * Fantastic Four introduced a family team where the members clash and bicker from time to time. Also, The Thing pioneered the idea of a superhero who viewed his powers as a curse.
 * The Incredible Hulk got a lot of attention as an ambiguous hero who wasn't really a superhero or a monster, but rather something in between. He was also a counter culture symbol in his early days.
 * Point of order: it is generally accepted that Barry Allen, the second Flash, was the character that kicked off the Silver Age, complete with sleek, form-fitting, cape-less costume, more scientific...ish...origin, and a Rogues Gallery of gimmick villains.
 * Jack Kirby's move to DC. The New Gods is often considered the beginning of the Bronze Age.
 * Watchmen and Batman: The Dark Knight Returns more or less ushered in the Dark Age of comicbooks. Kingdom Come, in turn, would end it.
 * Peanuts changed Newspaper Comics permanently. It gave strips the license to address deep and (sometime) dark issues and not just be simple gag-a-day escapaism. However, Charles Schulz's signature simple artwork gave newspapers the idea to reduce the size of the comic panels and force all the future artists to simplify their artwork to the point where all the art look like rushed cut-and-paste jobs.
 * And again with Calvin and Hobbes, which marked the beginning of the pushback against the "Schulzian" simplification.
 * Harvey Pekar's American Splendor showed that comics could depict adult life without idealizing it.
 * The Adventures Of Luther Arkwright was an independant New Wave style Science Fiction comic made by Bryan Talbot in the 70s, the techniques and story telling he used have had large impact on many other writers and artists. Warren Ellis has said "LUTHER ARKWRIGHT invented the tools. ARKWRIGHT informs Alan Moore, Grant Morrison, Neil Gaiman, Garth Ennis, me, and all the rest of us. It's probably Anglophone comics' single most important experimental work."
 * R.Crumb and others started the alternative and art comix movement in the late 60s.
 * The French Métal Hurlant magazine and its American equivalent, Heavy Metal, introduced a lot of influential science fiction and fantasy comic book creators like Moebius, Enki Bilal and Richard Corben.
 * 2000 AD started in 1977 and has been the most popular Britsh comic of the past few decades, granted it's faded a bit but it was the starting place for influential creators like Alan Moore and Grant Morrison.
 * More than just them, too. Chances are if there's a significant British creator from the last 30 years, he's almost certainly done something for 2000AD, even if it was just a one-shot Future Shock.
 * Alan Moore starts writing Swamp Thing. From one writer no one in America had heard of on a dying thrid-string title at DC we eventually got the whole of Vertigo Comics, Marvel's Max Imprint and not a few smaller publishing houses (Avatar, for example).
 * Chris Claremont starts writing the X-Men. Marvel Comics had been soap operas before that point, but Claremont's writing made the soap truly operatic in scope. Mainstream modern superhero comics, including the deconstructions of Alan Moore and others, were changed forever by the popularity of Claremont's writing style. (Yes, Byrne's art had something to do with it too, but Claremont stayed on the title a lot longer and had a lot more influence.)

Fan Works

 * "A Fragment out of Time" published in Spockanalia (a Star Trek fanzine running through the seventies) was the first known Slash Fic to hit wide distribution. Virtually every Yaoi Fangirl can thank the unknown fanfic writer.

Film
"[Harry Potter is] a film series that, for better or worse, seems to have kicked off and excelled at every major trend in modern movie-making for the last decade. Things like the boom in the Fantasy genre, to the reliance on recognized franchise names, to the idea of long-running cinematic continuity, can all be traced back to this one game-changing production. Like it or not, the entire scope of movies are now living in the world that Harry Potter created."
 * Heavens Gate, although not for the same reasons as most of the other examples: it was so bad, it killed the Hollywood Western, United Artists as an independent studio, and director Michael Cimino's career. It and other high-profile flops (One From the Heart, Sorcerer) also killed the auteur period in Hollywood.
 * Wes Craven made Scream in an effort to kill the slasher movie once and for all. It did the exact opposite, breathing new life into a once-dying genre and starting the late '90s/early '00s Post Modernism craze in horror.
 * Before that, Halloween did the same thing, basically starting the modern slasher genre. Two years later, Friday the 13 th turned the slasher flick into a Horror staple by focusing on the exploitation part of it.
 * Die Hard did this for the action movie. Sure, there were smart thrillers beforehand -- Die Hard itself could be seen as something of a remake of North Sea Hijack—but after it came out, there were far fewer action films that featured invincible, unstoppable heroes (Schwarzenegger, Stallone) whose plots depended entirely on Ass Pulling solutions out of thin air than there were before. Plus, not many films rewrite the rules for the genre so heavily that an entire subgenre forms around them.
 * A decade later, The Matrix did the same thing, introducing mainstream Western audiences to Hong Kong-style gunplay, fight choreography living up to Asian action film standards of sophistication, and codifying the use of Bullet Time.
 * And just a few years after that, The Bourne Identity took action movies in the other direction, filling them with grit and stripping them down to basics in a seeming backlash against the over-the-top style of The Matrix. It also took cinematic Spy Fiction away from the flashy, over-the-top "Martini" style seen in the Pierce Brosnan Bond films and more in a "Stale Beer" direction, to the point where even the most recent Bond films followed its lead.
 * Forbidden Planet was the film that revolutionized film and television science fiction.
 * Sergio Leone's Dollars Trilogy. These films weren't the first deconstructionist Westerns—the classics High Noon and The Searchers came out a decade before them—but they left a far more lasting impact on the genre than those two films did. All of a sudden, the Black and White Morality that was nearly omnipresent in the genre vanished, replaced with the grittier, more morally gray attitudes seen in such films as The Wild Bunch, High Plains Drifter and, much later, Unforgiven. Every single Western made since the mid-'60s owes something to Leone's masterpiece.
 * Star Wars. While Jaws is usually regarded as the first modern "blockbuster" movie, this was the one that proved that kids—a demographic ignored by most 1970s movies—were audience members too, that merchandising spinoffs were a potential gold mine, that escapist sci-fi wasn't as disposable as once thought, and that fantasy in general was an untapped resource. The whole George Lucas Throwback genre originated here, and while Follow the Leader meant there were many crappy imitators within the years that followed, it did lead directly to Superman getting a big movie of his own, thus launching the rise of cinematic comic book adaptations. It was also helped launch the revival of rival series Star Trek. Indeed, some blame this movie for hastening the end of the "New Hollywood" era and leading to the dumbed-down Summer Blockbuster mentality of the industry today. Especially once the sequels arrived...
 * Furthermore, Star Wars fundamentally changed how movies were made because of the huge success the franchise had with marketing. Sure, the movies were profitable, but the real money was made in action figures and toys and posters and other kinds of merchandising. Any kind of family-friendly blockbuster is going to have a cute character of some sort designed to appeal to children and sell toys to them.
 * The Superman movie proved once and for all that comic book adaptations didn't need to be cheesy or silly, with terrible budgets & special effects.
 * Although there have been occasional big budget comic book movies dating back to Superman (and filmed serials before that), the current boom in comic films got its start when Blade was a hit at the box-office, followed shortly thereafter by X-Men.
 * Blade's influence can be seen thusly: Prior to Blade, the only theatrically-released movies based on Marvel Comics-owned properties, ever, were a Captain America (comics) serial from the 1940s, Red Sonja, the 1989 Dolph Lundgren version of The Punisher, and Howard the Duck. Now, you can't have a summer without one.
 * In an amazing coincidence, just as Watchmen and The Dark Knight Returns took comic books in a Darker and Edgier direction, The Dark Knight and the film adaptation of Watchmen seem to be having the same effect on comic book movies.
 * Whoa whoa, Batman easily did that first twenty years earlier.
 * Both films have marked major turning points for the comic book movie. The influence of Tim Burton's Batman cannot be denied but neither can the influence of the The Dark Knight Saga.
 * While we're still on the subject of comic book movies, the notorious Batman and Robin has been described as the moment when Hollywood realized that they couldn't just churn out crappy adaptations and expect the "built-in" fanboy audience to eat them up. Rather, they had to start treating their properties with at least a modicum of respect.
 * Psycho and Night of the Living Dead are, along with the ditching of the Hays Code and its replacement by the MPAA, widely credited for helping to turn the Horror genre from "stories that are a bit spooky and feature the odd death" to "stories where Anyone Can Die, deaths are bloody and brutal, and sometimes even The Bad Guy Wins."
 * Each of those films also helped to launch their own sub-genres of horror -- Psycho is considered to be the Ur Example of the slasher genre, while Night single-handedly invented modern zombie fiction.
 * Shrek ushered in a period of Deconstruction for fairy tales, resulting in Fractured Fairy Tales such as Enchanted, Happily N'Ever After, and Hoodwinked. The genre has recently begun Reconstruction, with The Tale of Despereaux, The Princess and the Frog and Tangled.
 * Shrek is also blamed by fans of traditional animation for ending the dominance of traditional animation and about the rise of All CGI Cartoons laden with pop cultural references that would become dated within months, an over-reliance on Toilet Humor, overuse of Parental Bonus and Getting Crap Past the Radar to the point where it gets annoying, and gratuitous celebrity casting. Granted, Warner Bros. had done pop cultural references back in the Golden Age of Animation; Disney often cast big name celebrities in their films since Aladdin, and pretty much EVERY animation studio has slipped crap past the radar in their films, but Shrek and similar movies are the culmination of these trends, for better or for worse.
 * Snow White and The Seven Dwarfs showed that not only can animation be entertaining and longer than 5 minutes, but that the audience can be emotionally connected with animated characters.
 * The Harry Potter film series arguably did this for the entire Summer Blockbuster. At least, in Moviebob's opinion:


 * The Potter films most clearly sparked a trend towards more faithful and straightforward adaptations of novels, particularly fantasy novels aimed at children and/or young adults. The prior trend of combing seperate installments of a novel series into one film was killed in favor of adapting each novel individually in the hopes of creating a money-spinning movie franchise. When the live-action Chronicles of Narnia movies were first planned, Executive Meddling was aimed at relocating the story to America. But after the success of the first Potter film, the executives suddenly didn't have a problem with keeping the British setting of the novels.
 * Together with the aforementioned Potter, the Lord of the Rings films greatly raised the prestige of fantasy movies, much as the books had done for fantasy literature. Before then, fantasy films had mostly been (at best) B movies like Conan the Barbarian or kids' films like The Neverending Story. After The Return of the King went home with eleven Oscars, though, few people could successfully argue that a movie wasn't True Art just because it featured elves, trolls and wizards.
 * Blade Runner was a disappointment in a crowded summer box office when it came out. Repeated showings on cable and its release on video not only made it one of the first films to develop a strong cult following that way, but introduced the first entirely new way of visualizing the future in sci-fi films since Metropolis a half-century earlier. Not only did its wet streets reflecting neon signs at night get copied widely in other films, commercials and music videos during the 1980s, it arguably influenced the look of urban space in the actual real-world future (See Times Square, ca. 2008).
 * The Alien series firmly established in futuristic stories, any major female character is expected to pull their weight in the face of danger or combat like Ellen Ripley.

Literature

 * The Lord of the Rings wasn't the first fantasy novel, but it set up most of the devices of modern fantasy.
 * And of what Tolkien didn't start, CS Lewis probably did with The Chronicles of Narnia. Not surprisingly, the authors were friends.
 * Terry Brooks was the first fantasy author to be a best-selling author, and is considered to be the author that turned fantasy literature from a fringe cult phenomenon into a real industry. Interestingly, although his first Shannara book was heavily influenced by Tolkien, he also introduced some fantasy conventions of his own, such as a less formal writing style.
 * John W. Campbell, a popular science fiction writer and magazine editor, is generally credited by Asimov, Clarke, Heinlein, and other science fiction writers as being responsible for nurturing their talents and for bringing higher standard of storytelling to the science fiction genre, which had previously consisted mostly of utopian literature, stories of aliens and fantastic gadgets, and space Westerns. Genre historians often date the beginning of science fiction's Golden Age as being 1938, the year Campbell assumed editorship of Astounding Science Fiction magazine.
 * Neuromancer more or less created the Cyberpunk sub-genre of Sci Fi.
 * Don Quixote was not only the first "modern" novel, but it also single-handedly killed "knight stories" (Chivalric Romance, adventure stories with a Knight in Shining Armor as the main character—think King Arthur & co.)
 * Moll Flanders changed the novel forever. Defoe's realism made it unlike anything which had gone before; his plot was completely original, in an age of reworking classic plots; and his narrator was something new and very interesting.
 * H.P. Lovecraft went from simple stories of the macabre and ghost stories to Cosmic Horror, which changed the face of the horror genre forever.

Live Action TV

 * Star Trek the Original Series, despite it not doing spectacularly well in the ratings, spawned numerous short-lived imitators (a few coming from Gene Roddenberry, Trek's creator) in comic books and television. During the '70's it served as the template for Science Fiction television in America (and to a lesser extent, the rest of the world) until the advent of Star Wars, though the clones tended to only last for a season or two. Even the original Battlestar Galactica Classic and other works influenced by Star Wars showed its influence. Its impact lasted as late as the '90s, though more in the form of television reacting against the series.
 * Star Trek's influence, however, would go on to shape far more than science fiction as a genre; not only is it the Trope Codifier (and Trope Namer) for the Power Trio, but things like automatic doors, Kindle, iPods, bluetooth, cell phones and laptops were all first conceived for Star Trek. Its impact even goes beyond pop culture and technology; Dr. Mae Jemison, the first African-American woman to work in space, was inspired to become an astronaut after seeing Lieutenant Uhura on television as a little girl.
 * Doctor Who had a similar status in the United Kingdom. It, too, spawned numerous homages, ranging from the long-running but much-mocked The Tomorrow People to the dark and cerebral Sapphire and Steel, as well as many other less well-known examples. Similariy, the 2005 revival is credited with restoring Saturday night family dramas to British television as others began to capitalize on its success.
 * Star Trek and Star Wars were (and still are) considered the bastions of American Science Fiction, both being notable for their 'optimistic' views. Babylon 5 and Star Trek Deep Space Nine started taking sci-fi in a new direction, away from the space opera/Western in Space concept and made them more character driven dramas, in the vein of cop shows almost. This started a slow but steady shift in the television sci-fi genre that later yielded Farscape, The X-Files, and culminating in the reimagined Battlestar Galactica and Stargate Universe.
 * In turn, Babylon 5 can arguably be credited for the current boom in serialized storytelling on TV.
 * Lost popularized the idea of shows built around long-term myth arcs that jerk the viewer's mind around, as well as bringing sprawling, Soap Opera-style storylines into TV sci-fi. While it has its antecedents (The X-Files, the aforementioned B5), the boom in such programming after LOST's success shows why the trope is called the Noughties Drama Series Drama Series.
 * In the late '90s and early '00s, HBO shows like The Sopranos, The Wire and Oz, with their focus on cinematography, acting, and complex themes and storylines developed through sharp writing and in-depth characters, proved that television productions can be just as good as Hollywood movies, and that cable television could seriously compete with the broadcast Networks on their own turf.
 * Seinfeld changed the the way Sitcom characters and stories are portrayed so completely that the original series seems derivative in the new context it created.
 * For better or worse, Lizzie McGuire and That's So Raven invented the modern-day Idol Singer-centric tween sitcom.

Music

 * The Beatles did this for pop and rock music. Which of their albums is most influential is debatable, but the majority seems to settle on Sgt. Pepper's Lonely Hearts Club Band for the numerous innovations it introduced to music, as well as still being considered to be one of, if not the, best mixed albums ever. Now, consider for a moment how much more sophisticated the technology for mixing has become 40 odd years later. (Keep in mind this only applies to the mono version.) The White Album is also a fair contender for the title of "best Beatles album."
 * It's also debatable whether it was just them or the whole of The British Invasion. Those who argue the former say that there wouldn't have been a "British invasion" without The Beatles, while the latter point out that the Beatles were only one band out of many, and that The Rolling Stones, The Who, and other bands also deserve recognition. That said, while they certainly weren't the only worthy or notable British act of the 1960s, the Beatles' success (not only as the first British rock act to significantly break into the American market in a lasting way, but having achieved numerous number one hits in the process) certainly paved the way for the others to build on their success.
 * The Beach Boys' Pet Sounds was an inspiration for the Beatles' Sgt. Pepper to become a Concept Album. It was not exactly narrative, however, and also not the first concept album. Take for example, Johnny Cash's Ride this Train or Ray Charles's The Genius Hits the Road released about six years before. The Ventures were also making concept albums years before Pet Sounds.
 * This also represented something of a friendly rivalry between the Beach Boys and the Beatles, or at least Brian Wilson and Paul McCartney, as they began to engage in a constant process of trying to one-up the other, in the process producing some great music.
 * Eric Clapton's short, but legendary stint with John Mayall and The Bluesbreakers produced only one album often called Beano. The album is credited to be the first album to feature modern rock guitar. Eric Clapton was the first guy to dare to crank up his amp and take his space. Many people say Jimi Hendrix was the first modern rock guitar player, but he got his inspiration from hearing this album.
 * Eddie Van Halen's 80 second guitar solo on Van Halen's first album was the "Eruption" heard round the world. Shredding was born and rock guitarists became virtuosos in their own right. While the style fell out of favour in mainstream rock in the early 1990s, it's still a major element of various metal and progressive rock scenes worldwide.
 * The Grunge band Nirvana is often credited with putting the final nail in the coffin of Hair Metal and sparking a return to Three Chords and the Truth.
 * Rap music received plenty of media attention for most of The Nineties, but most of it was on the back of the controversy it generated. Then Biggie and Tupac got shot, and Sean "Puffy" Combs released his hit album No Way Out, and suddenly Glam Rap became the dominant form of "urban" music on the radio for the rest of the decade and the start of the next.
 * The Nineties as a whole were a turning point for rap music. The decade introduced a large array of sub-genres that showed that rap could be more than just block party music, and that it could also have strong messages and themes (much to the chagrin of fans who were use to it just being "fun"). It also saw the growth in rap's popularity outside of New York City, resulting in what is arguably the climax of the Golden Age era.
 * Chuck Berry's Johnny B. Goode brought the Epic Riff into rock music once and for all, and showcases a guitar style that, even after Hendrix and Clapton, would barely sound out of place today.
 * Bob Dylan's Highway 61 Revisited, especially "Like a Rolling Stone."
 * Bob's early output in general has often been cited as a major influence in bringing true art and poetry into pop music writing. It can't be a coincidence that his rising popularity in the first half of the 60's coincided with something of a move away from the up to then ubiquitous hot cars and fast women thematics, when people started listening to songs like "Blowing in the Wind" and "Mr Tambourine Man" instead.
 * Almost all of Metallica's first three albums could count as this for thrash metal, being Trope Codifiers for the genre in different ways.
 * Black Sabbath's first album for heavy metal. If a heavy metal band says they're not influenced by them, they're lying.
 * Venom may have been the trope namers, but it was Mayhem's album De Mysteriis Dom Sathanas that really defined what Black Metal would come to be known as.

Professional Wrestling

 * ECW brought hardcore wrestling to North America, made luchadores popular in the United States, and made professional wrestling Darker and Edgier at a time when the two biggest promotions, the WWF and WCW, were still putting out an altogether Lighter and Softer, more comic-book-ish product. Amazingly enough, WCW, part of the Time Warner media empire, and WWF, a multi-million dollar entertainment company in its own right, ended up taking their cues from a tiny promotion that ran shows out of a converted bingo hall in South Philadelphia.
 * The WWF also had one at some point between 1996 and 1998, but mileage varies on what exactly it was. Some people cite Steve Austin's victory at King of the Ring 1996 and resulting Austin 3:16 promo, which made him the only thing to rival the New World Order in popularity. Others cite Austin's match against Bret Hart, face of the WWF along with Shawn Michaels, at Wrestlemania XIII, when Austin turned face and Hart heel. Others will cite the formation of D-Generation X, an edgy, raunchy stable that was somewhat NWO influenced (it had members of The Kliq in it as well, after) and feuded with the Hart Foundation, Bret Hart's group. Resulting from that feud was Michaels and Hart's match at Survivor Series 1997, Hart's last match in the WWF under his current contract. The match was to end ambiguously and Hart was to surrender his championship the next day on Raw, but Michaels, Vince McMahon and Triple H conspired to end the match without Hart's knowledge. This event created the Mr. McMahon character and a decade's worth of unmitigated hostility between Hart and those involved. The final event is Austin's match against Michaels at Wrestlemania XIV, when Austin defeated Michaels and in the words of JR "The Austin Era (had) begun." This event kickstarted the Austin-McMahon feud, which would be the focal point of the entire company for three years, in the company's most successful or second most successful era, The Attitude Era.
 * Similarly, at and before Wrestlemania X-Seven, the Attitude Era ended. Vince purchased WCW, the company's chief rival, and at Wrestlemania, one of the greatest PPV's in history, Austin faced The Rock for the WWF Championship, unbelievably, Stone Cold turned heel in his hometown and sided with McMahon to beat Rock. The central feuds of the Attitude Era, both in real-life and kayfabe, had ended within a week of each other.

Sports

 * This has happened multiple times in Baseball.
 * In the 1920s, Babe Ruth popularized the idea of the home run, shifting much of the game's offensive focus from baserunning speed to long-ball power.
 * Jackie Robinson's breaking down the color line was this for more than just the sports world. Not only did it create interest in successful Negro League players, it was also an early turning point in white America's acceptance of the idea that black people weren't so different from them.
 * The airing of Major League Baseball games on television in The Fifties destroyed most of the minor leagues, who couldn't compete with the bigger games being shown on TV.
 * The move of the New York Giants and the Brooklyn Dodgers to, respectively, San Francisco and Los Angeles in 1957 will probably never be forgiven by New York sports fans, but it helped popularize baseball outside the East Coast and the Midwest and led to a surge of teams moving to sunny Southern and Western cities, securing the sport's national viability for the rest of the century. It also effectively destroyed the Pacific Coast League (which was, until then, seen as a growing rival to Major League Baseball), pushing it down into the minors and securing MLB's position as the dominant baseball league in the US.
 * Maury Wills helped repopularize the stolen base in the early 1960s.
 * Rollie Fingers was central to the idea of the dedicated relief pitcher/closer in the 1970s, paving the way for the modern game's reliance on the bullpen.
 * The 1975 World Series between the Cincinnati Reds and Boston Red Sox, one of the most exciting matchups in sports history, was the moment at which television finally understood how to broadcast baseball. Carlton Fisk's iconic home run in Game 6 provided a catalyst in getting camera operators to focus most of their attention on the players themselves. It's no coincidence that, after the '75 World Series, a new lucrative TV deal involving not just NBC, but ABC was made.
 * The early success of Hideo Nomo paved the way for Major League Baseball's interest in Japanese players.
 * In Australian Rules Football, the 1970 VFL Grand Final is often seen as the point at which a major shift in the game occurred. Carlton, 44 points down at half time, came back to defeat Collingwood after a rousing half-time speech by coach Ron Barassi in which he exhorted the players to handball - and ever since then, the handball has been a much more prominent feature of the game, sometimes more common in a match than kicking the ball.
 * Several players have shifted the way Ice Hockey gets played. Highlights include:
 * Bobby Orr popularizing the concept of defensemen supporting offensive plays
 * Patrick Roy is credited for popularizing the butterfly goaltending style
 * Wayne Gretzky for his use of the behind-the-net goal setup.
 * In American Football, initially field goal kickers kicked the ball towards the goal posts straight on, the results being that most field goals didn't have much distance and their accuracy was iffy at best (60% or so). Then Pete Gogolak and others introduced the angled, soccer-style kick for field goals, increasing distance and accuracy and immediately improving the viability of field goals tremendously. As of today the soccer-style kick is used professionally almost exclusively.
 * And the place kick (straight on) replaced the drop kick, where the kicker dropped it like a punter and let it hit the ground before kicking it. The last time it was used was by Doug Flutie as an homage.
 * Certain single games and/or series have breathed life into otherwise stagnant or dying leagues. The 1979 NCAA basketball championship between Larry Bird's Indiana State team and Magic Johnson's Michigan State team breathed new life into college basketball. Five years later, the 1984 NBA Finals between Bird's Boston Celtics and Magic's Los Angeles Lakers helped spark a revival in the NBA, which had languished in popularity before the pair entered the league.
 * The New York Jets' upset victory over the Baltimore Colts in Super Bowl III arguably lent the American Football League credibility against the more established National Football League. It helped that Jets' quarterback Joe Namath's "guarantee" that the Jets would win added to the pregame hype (unheard of in the previous two games). The Kansas City Chiefs' win over the Minnesota Vikings the following season proved that it wasn't a one shot, fluke deal for the AFL leading up to the eventual merger in 1970.
 * The High Jump was revolutionized by Dick Fosbury in 1968. It's weird as heck to watch someone do a Fosbury Flop (It involves turning around at the point of the jump and going BACKWARDS over the bar), but it manages to allow jumpers to jump as much as 25% higher than they would be able to jumping straight forwards over the bar.
 * The 2005 fight between Forrest Griffin and Stephen Bonnar on the undercard of the The Ultimate Fighter finale, the first ever live-televised MMA event. Their legendary, back-and-forth brawl over a UFC contract made instant fans almost overnight, and it's been documented that ratings spiked during the fight as fans were frantically calling other people to point them to this fight. UFC president Dana White credits this fight as perhaps the most landmark moment in MMA history, and the turning point that launched it to such great, mainstream heights.
 * In Soccer, the 1953 match between England and Hungary is widely regarded as being the point when the modern game came into being. The Hungarians playing a then unknown tactical style totally outclassed the English, who until that point had never been defeated at home by a team from outside the British Isles. In the aftermath the old English formations and tactics vanished entirely, and the continental tactics, training and equipment became the standard around the world.

Theatre

 * Oklahoma changed the musical theatre genre from fluffy entertainment into legitimate theatre.
 * Well, Oklahoma gave musical theatre the format of the use of song, dialogue, and dance, but it was Show Boat that first made musical theatre into legitimate theatre.
 * Oklahoma was not the first musical to use song, dialogue, and dance - those three things were in every musical. What Oklahoma did was integrate those three elements in a mature and realistic fashion (well, as realistic as breaking into song ever can be.)
 * Aeschylus did this for drama -- 2500 years ago—when he made drama using contemporary, rather than mythical, themes.
 * Euripides reinvented theater again, by focusing more on the characters and their motivations, adding larger casts, and making the dramatic aspects much less subdued.
 * Cirque Du Soleil accomplished this trope twice over:
 * Starting with its 1987 tour Le Cirque Reinvente, Cirque did a lot to raise circus out of the kiddie entertainment ghetto it had fallen into in North America. Now, not only are there many successful "contemporary circus" troupes/companies that play to a wide variety of audiences, but blatant imitators of Cirque's style (which was derived from European and Asian circuses) have sprung up.
 * Their first Las Vegas resident show, Mystere, helped change that city's entertainment scene. Siegfried and Roy's magic show at the Mirage had opened four years prior and was also a big game changer after years of increasingly stale showgirl revues, but Mystere was actually taken seriously as theater, to the point that Time magazine's theater critic named it one of the best shows of 1994. While it would lead to many acclaimed sister productions in the city, other Vegas casino-hotels imported such productions as Blue Man Group, Jersey Boys, and The Lion King, often with huge success, resulting in a much more diverse range of entertainment for tourists.

Video Games

 * In the field of video games, Super Mario Bros.. defined the 2D platformer, as well as ensuring the resurrection of the video game home console in the United States after The Great Video Game Crash of 1983.
 * And then another Mario game, Super Mario 64, set the standard for 3D platformers for years to come, and was the first 3D platformer to successfully use a joystick.
 * Yet another Mario game, New Super Mario Bros, proved with its high and unexpected popularity that looking to gaming's past is not a sign of creative stagnation. Hence, the massive influx of retro-flavored games afterward, including Nintendo's own Donkey Kong Country Returns.
 * Prince of Persia: The Sands of Time made platforming "realistic" with its use of parkour, and set the stage for, among other things, the Tomb Raider reboot and Uncharted.
 * Back in 1989, the first Prince of Persia did the exact same thing, with its realistic platforming and fighting.
 * Final Fantasy VII rewrote the rulebook for the 3D RPG genre, popularizing highly cinematic presentation enabled by CG rendering and the newly increased storage space of CDs, and dynamic camera angles and movement in battles presented in 3D.
 * Street Fighter 2 altered the face of the Fighting Game, shifting focus from side scrolling brawlers onto one on one fights, varied character rosters, and competitive two player modes. It also had a Good Bad Bug that let you "Combo" moves together.
 * Virtua Fighter likewise proved that fighting games could easily make a transition into 3D, in addition to showcasing more natural forms of combat as opposed to the fireballs and wuxia of its 2D brethren.
 * Half-Life reshaped the First-Person Shooter introducing scripted setpieces and the illusion of intelligent AI, and story driven progression rather than a simple sequence of key and switch hunts.
 * The FPS genre seems to be as impressionable as wet clay. After Half-Life it was once again redefined by Halo, bringing in regenerating health and losing the massive weapon inventories of older contenders.
 * And a year later, Metroid Prime also helped redefine the FPS by successfully fusing it with the Adventure genre, creating a first-person shooter where the focus was not on combat, but rather exploration and puzzle-solving. Those had long been staples of video games, but Metroid Prime really was the codifier for their inclusion in the FPS genre. To this day, almost every modern FPS plays Follow the Leader trying to catch up to Halo and Metroid Prime.
 * Rarely does a licensed game redefine conventions. Yet this is exactly what GoldenEye did long before Halo, showing that consoles were perfectly viable for a First-Person Shooter while setting the standards for every shooter of its generation.
 * Doom was the first FPS to offer multiplayer (via LAN or dial-up modem). This new mode of play proved to be hugely popular. Because of Doom virtually every FPS released since then includes a multiplayer mode, and many FPS fans buy games solely for the multiplayer and never play the single-player.
 * Castle Wolfenstein invented the stealth game genre, but it wasn't until the success of Metal Gear Solid and Thief that the genre began to attract attention. Other stealth game series, like Splinter Cell and Hitman, have continued this with quirks of their own.
 * PC gaming was generally seen as inferior to console gaming until the advent of Doom, which was made by, of all things, a Shareware company, causing gaming companies everywhere to rethink their business model.
 * On that note, shareware in general (where you gave away part of your program for free, and the user would pay you money for the full thing if they liked it) was seen as a really stupid idea that could never possibly make money. Apogee Software and Epic MegaGames came along and proved that the model could be profitable, at least with games. Apogee made a lot of money with the game series Kingdoms of Kroz, and Epic with ZZT. Keep in mind this is way BEFORE the days of the Internet, which made distributing shareware easy. Apogee later changed their name to 3D Realms and created Duke Nukem 3D, and Epic went on to create the Unreal and Gears of War series.
 * Game-wise, Duke Nukem (Apogee), Jill of the Jungle (Epic) and Commander Keen (Id) popularised Shareware. One from each major company.
 * Similarly, Quake was the first FPS game with built-in internet multiplayer, which is now the defining characteristic of the genre.
 * Gears of War seems to have lead third person shooters as a genre to strategic cover-based gameplay.
 * Dragon Quest took RPGs down a completely different path. Its emphasis on story and simplistic combat was a major culture shock for US gamers when they got their hands on it (western RPGs at the time consisting mainly of shallow stories and cripplingly complex gameplay), but it definitely had a following, and it spawned the subgenre we now refer to as the JRPG.
 * The Xbox Live service (and its child service, the Xbox Live Arcade) provided two previously rare functions on consoles—it allowed for the onset of downloadable content expansions to console games, and it allowed for the download of small games directly to a console's hard drive, starting with titles such as Namco arcade games. With the Xbox 360, this eventually allowed for the download of entire Xbox games, but this and several other download networks ushered in a new era of independently produced games, which themselves are sometimes deconstructions and reconstructions of classical video-game concepts. The industry has essentially come full-circle.
 * For the Interactive Fiction genre, Photopia. Before Photopia, games often used Mind Screw surrealism or High Fantasy loosely bound by a huge Story Arc. After Photopia, plot and puzzles became more important to the feel of a game, and slice-of-life realism overtook surrealism as the most popular environment in Interactive Fiction.
 * The release of Inform (and much more so Inform 7) revolutionized the medium, if not the genre. It made it possible for non-programmers to write Interactive Fiction software.
 * Steam did a lot to revive PC gaming in the Turn of the Millennium. Before it became popular, PC developers were fleeing to consoles en masse due to both the growing threat of piracy and, later, the backlash that intrusive DRM systems caused within the gaming community. Steam offered not only a relatively consumer-friendly form of DRM, but a whole slew of other features (unified friends lists, achievements, etc.) that had previously been exclusive to consoles. As a result, developers felt more confident releasing their games on PC through Steam, with the knowledge that they were not only tougher to pirate, but that, even when they were inevitably pirated, the pirate copies would lose their Steam functionality in the process.
 * Steam also helped to create the market for indie gaming by offering a way for small developers to get their games to consumers without the costs and hurdles associated with retail stores. Xbox Live Arcade and Playstation Network quickly followed its lead, spreading the indie love to console gamers.
 * You have Tokimeki Memorial to thank for Dating Sim girls who actually have personalities beyond "living love doll".
 * ...and Kanon to thank for giving the male protagonist a personality, as well as (and the two are connected) making Porn with Plot Eroge just as marketable as Porn Without Plot games (though the developers had previously done ONE -kagayaku kisetsu e-, Moon., and Dousei before forming their own studio, none of these games had the impact that Kanon had).

Western Animation

 * The Disney version of The Little Mermaid was a surprise sensation in 1989, revitalizing interest in animated features. For years afterward, its musical fantasy structure was the default setting for Western animated features. It was eventually overtaken by the Pixar CGI boom, but arguably no CGI film has had the kind of positive impact on the entire genre that Mermaid did.
 * Speaking of Toy Story, it spawned the entire CG boom in animation, which eventually took over Western animated film.
 * The Simpsons struck a huge blow against the Animation Age Ghetto, proving that animated shows based around adult humor can be successful.
 * The Dover Boys is a double turning point for American animation. It marks the point were Warner Bros's animators stopped aping Disney and started experimenting with much more stylized action. It also marks the point when Chuck Jones went from the junior director who did the Sniffles the Mouse cartoons to a major innovator.
 * Speaking of Warner Brothers cartoons, Tex Avery revolutionized both the Warner cartoons and the animation industry itself. At a time when Warner and almost all other studios were hell-bent on imitating Disney, and in which Warner cartoons in particular were suffering from deathly mediocrity, Avery came along in 1936 with his zany, faster-paced, smartassed, fourth-wall-breaking comedy, and cartoons haven't been the same since. If you watch the Warner cartoon library in sequence and look at what the studio was doing by 1937 or '38, it's amazing to think that this same studio had been producing terminally boring cartoons just two or three years earlier. When Warner cartoons finally became funny, they had Tex to thank for it.
 * The short lived Mighty Mouse: The New Adventures completely overhauled the expectations of what a television cartoon could do and began the practice of cartoonist-controlled animation and en-masse pop culture references.
 * Batman: The Animated Series allowed comic book superhero cartoons animated series to move past the Animation Age Ghetto of the Superfriends, with heroes and villains that have complex motivations and (often) tragic back stories, and spawned a very well-remembered franchise
 * Doug started a trend for many Slice of Life shows in the 1990s.

Real Life

 * The Great San Francisco Earthquake for California. Before the quake, San Francisco was the largest city on the West Coast, and Los Angeles' population was less than a million, nowhere near the second largest city in the United States. The quake and the Hollywood boom were instrumental in shifting the population southward.
 * The Hurricane of 1900 that struck Galveston, Texas sent it into a long decline while turning Houston into a booming port town. NASA and oil would finish the job.
 * The construction of the Houston Ship Channel played a significant role in the shift as well.
 * The Black Death decimated Europe's population in the mid-1300s with repercussions felt for decades. Some of these still felt today, according to various scholars, may have included:
 * The foundations of the Protestant Reformation and the weakening of Church authority in general
 * A rise in anti-Semitism and other prejudices
 * The rise of the middle class
 * The Green Revolution
 * The Industrial Revolution
 * People of European ancestry having greater resistance to HIV
 * The plague also returned periodically for centuries afterward, leading to boom/bust population cycles which didn't really end until the colonial age.
 * The fall of Constantinople to the Ottoman Turks in 1453 is widely considered by historians to mark the official end of the Middle Ages and the final nail in the coffin of the Roman Empire (the Byzantines always considered themselves to be Romans, referring to their territory as Romania), which had existed for nearly 1500 years if one combines the ruling years of Ancient Rome and the Byzantine Empire together.
 * The massive outflow of Greek scholars from Constantinople greatly influenced and accelerated the birth of the Renaissance in Europe.
 * The sudden removal of the Byzantine Empire as a buffer-zone between Christian Europe and the Muslim Middle East, as well as the removal of the main overland trade-link between Europe and Asia, led to rapid advancements in warfare and seafaring technology within Europe for the first time in centuries.
 * The fact that the Ottomans were now blocking the Silk Road led European navigators to pursue alternative routes to the riches of the Far East, which brings us onto...
 * Perhaps most famous of all, Columbus' discovery of the West Indies in 1492 was The Beginning Of The End for every major civilization in North and South America, along with much of the native populations. At the same time, northern Europe entered a new era of vast riches and world domination.
 * The Peace of Westphalia originated the modern conception of state sovereignty (including territorial integrity and modern diplomatic relations), not just for the states involved, but all future states as well.
 * After World War II the world system of international relations was restructured drastically, with a new emphasis on not just sovereignty but (legal) equality between states. The old alliances of Europe were finished (World War I had previously shown how destructive they could be) in favour of new ones like NATO and the United Nations.
 * The Stature of Westminister in 1931, which redefined the relationship between the United Kingdom, the British Monarchy, and the various dominions which had once been colonies, marked the peaceful end of the most widespread empire in human history as the British Empire became the (British) Commonwealth.
 * On the 13th of September, 1989, a non-Communist government was formed by the Polish parliament, and the Soviet Union declined to force them to do otherwise. This kicked off the Great Politics Mess Up: within weeks that force variously called the Eastern Bloc, the Warsaw pact, the great enemy everyone had been planning to fight in World War III...simply went away. In just over a year later Germany was reunited, and a year after that the Soviet Union itself finally went into the dustbin of history, and the western democracies were stunned to discover that the Cold War was over, had never turned hot, and they'd won.
 * The American Revolution decisively changed international politics forever. It was the first modern democracy, and thus the Trope Maker for much of what we now think of as Western democracy. It directly or indirectly inspired revolutions for nearly a century and a half (from 1776 to 1918) - in particular the anti-monarchist nature of most of these revolts. It arguably represents the point at which guerilla warfare and firearms first met. And finally, it was the first time that an imperial European power was defeated by a non-European one.
 * The US Constitution's Bill of Rights and the French Declaration of the Rights of Man and of the Citizen, both of which were first drafted in 1789, are the Trope Codifiers for the modern concepts of liberal democracy and human rights.