Fixing the Game

Every animal has within its brain a system that helps it figure out how the world works. Once you learn how to do something, it fires off dopamines that make you feel good. Even pigeons and rats have the ability to figure out "push button, get food".

Some systems can't be beaten. The randomness at their core defeats the ability of even the smartest animal to figure out cause and effect. There's no cause, just the Random Number God. That's why we love gambling; it feels so good when you win. It's also why some people get addicted to gambling; it feels so bad when you lose.

Nevertheless, people have figured out as much as they can about gambling. The odds are very well known. One party's going to win, the other party's going to lose. Eventually. Face it, the casino wouldn't play the game if they weren't going to make money off of it. If you gamble, you're either lucky or a loser.

Some people Take a Third Option. They don't like to lose, and they don't like to gamble. If you cheat, you're not gambling and you're not losing. This is a trope that covers the many different ways people have found to not gamble. Super-Trope to Two-Headed Coin.

Examples of Fixing the Game include:

Anime

Played with in Gintama by having a man gifted with the ability to see the flow of luck, which turned out that he lost that ability a few years back and has been cheating at games since then.

Film

21 is a film entirely about counting cards. They also did that in Real Life. The consequences are exaggerated in the film.
Casino was set in a casino, a few people tried to cheat. The results were unpleasant.
Rounders features gambling and two best friends. One is a Professional Gambler. The other is a cheat.
Ocean's Eleven is a heist movie, but more than one person is a cheat. Danny finds Rusty teaching poker to celebrities. As soon as Danny sits down, the two of them rook the kids for a couple grand. Just for fun.
- The third film shows what happens when you try to cheat at one of Willy Bank's casinos. Although, Bank's not as imaginative in this regard as Terry Benedict.
Brick Top likes to run crooked boxing matches in Snatch. Turkish doesn't which is the reason people like him. Then he ends up in debt to Brick Top. Unfortunately, Mickey doesn't know how to take a dive. And he ends up betting on himself, reversing the fix.
Qui Gon Jinn from The Phantom Menace cheats at dice.
- Only an idiot would gamble with a Jedi. Not only can they rig the game with Mind Over Matter, but they can probably sense which way it's going to go.
The Polish film Wielki Szu is a story of a young man who becomes an apprentice to a cheater. It contains a quote that might serve well here "We played fair. You cheated, I cheated, the better man won."
In Bad Lieutenant Port of Call New Orleans, the main character catches a star college quarterback buying pot and blackmails him into shaving points on his next game. The quarterback can't go through with it and fakes an injury to get out of the game, but his team fails to beat the spread anyway.
In a flashback of Sgt Bilko, the titular character (played by Steve Martin) is known for rigging games and fights. He makes a deal with one of the fighters to take a dive, but his assistant screws up and pays the wrong fighter, who assumes that the payoff means that he should take a dive. The other guy then assumes that he'll be paid after the fight. The result is both guys circling each other for half an hour, afraid to land a punch. Finally, one of them punches the other out of habit... and both fall down. When Bilko's superior Thorne starts investigating, he finds the payoff in a locker belonging to the second fighter and confronts him about it. Just then the reporters burst into the locker room and take a picture that makes it look like Thorne is the one paying off the fighter. Thorne gets Reassigned to Antarctica and comes back bitter and itching for revenge.
- Naturally, since the movie is about Sergeant Bilko, he's portrayed as a good character, even though he does many illegal things for fun. Meanwhile, Thorne is merely trying to show Bilko for what he really is. Obviously, the film has to show Thorne going overboard and performing even more illegal acts than Bilko in order to establish him as the villain.
In The Hangover, Alan reads up on card counting while they're driving to Vegas. When they quickly need a large sum of cash to rescue their friend, Alan suggests they win it at the casino. He starts counting cards and ends up winning the money. When the security is moving to get him, his partners fake a health problem to divert the guards' attention, allowing Alan to get away.

Literature

In Harry Potter, Ludo Bagman comes up with a unique and brand new way to cheat. Just don't pay when you lose.
Skeeter Jackson from Time Scout loves to gamble, and he's not exactly an angel. After his Heel Face Turn, he ends up in a beautiful Victorian casino and plays a few rounds of craps to "keep his hand in". After he walks away from the table, he says that he threw three sets of dice and all three were loaded. One with heavy paint, one with a mercury tumbler, the third with shaved edges. The person he's with is astonished and appalled. Then Skeeter sits down to play poker and relates an amusing anecdote about a guy with a device up his sleeve.
In Aubrey-Maturin, Jack Aubrey plays some whist in the second book of his series. He accuses the people he's playing with of cheating. As one is a Smug Snake, The Gambling Addict, and a traitor, that's not implausible.
In Wheel of Time, Mat Cauthon occasionally gets accused of cheating. But he just very, very lucky.
In Harry Harrison's Deathworld series, the protagonist Jason dinAlt is a professional gambler, who uses his weak telekinetic ability to cheat at dice. He claims he can cheat at the roulette as well, but stopping a big wheel is more difficult than a small die. At the beginning of the first book, Kerk Pyrrus asks him to win 3 million for him. Unfortunately for them, the casino owner has connections in the planet's corrupt government. When Jason is on a big winning streak, the dealer keeps requesting new dice, hoping Jason's luck will change, culminating in him using dice that are obviously heavier on one side. With some quick thinking, Jason exposes the dealer by using a magnetic ashtray to reveal the rigged dice (the heavier side has metal in it). A security guard tries to intervene, but Kerk breaks his arm. Finally, when Jason has won all he can, they barely manage to get off-world by getting aboard a ship from a planet whose people absolutely hate the local Wretched Hive. Jason isn't shown gambling again.
In Walter Jon Williams's book Angel Station, the protagonists are down-on-their-luck brother and sister named Ubu Roy and Beautiful Maria (that is her full name). Maria is an "electronic witch", genetically-engineered with an ability to manipulate electrons with telekinesis. As a way of making money while they look for a contract, she plays a game (with a decent payout) that simulates navigating a ship through a field of black holes. Using her ability, she's able to win consistently by intercepting and altering computer signals before they appear on the screen. Ubu then suggests going for a big score and cheating at the roulette at a big casino on the titular space station. By that point, all casino games are electronic in nature, so Maria feels she has a good chance. She ends up winning a lot, but both are then taken to a back room, where it's revealed that the casino monitors all machines and detects any attempts at hacking them. Their only curiosity is the fact that Maria doesn't appear to have any equipment with her. They start beating on both of them. Even when Maria admits her ability, the casino owners don't believe her. They are thrown out the back of the casino badly beaten and without their winnings.
In a Star Trek Expanded Universe novel, it's revealed that Quark bans telepaths from his establishment, as they would have an unfair advantage at gambling.
In Red Seas Under Red Skies, Locke and Jean make a lot of money as gamblers. Cheating at cards also happens in the rest of the Gentleman Bastard Sequence, but more as a background color.

Live Action TV

One episode of Psych featured a Professional Gambler who got cheated at poker. Shawn then figures out that the game must be rigged, then he figures out how.
Angel accidentally lost his destiny and got stuck at the slots, feeding in money. Cordelia gave the machine a psychic nudge and Angel won.
On The Mentalist Jayne is a skilled cheater though he usually just prefers to use mind tricks to win. In one episode he is banned from a casino for counting cards and later tricks the murderer into implicating himself by beating him in a poker game. When the guy asks how Jayne did it, Jayne says "I cheated".
- Unlike the Casino example and many others, when Jayne is caught memorizing cards (which he's very good at doing), the head of security politely tells him that he may keep his winnings, but that he is no longer welcome at their establishment. After all, there's nothing illegal about remembering things.
Unforgettable: the lead character has an Eiditic Memory; in an Establishing Scene she gets in trouble at a casino for counting cards.
The Dukes of Hazzard: One time the Dukes took on a crook with a Travelling Casino in the back of a semitruck. They rigged the roulette wheel and had Uncle Jessie play when they blew the horn.
Mash: Klinger gets in a craps game in the back room at Rosie's bar and discovers that the dice are loaded, causing a fight to break out.
Only Fools and Horses:

Boycie: Where did you get those four bloody aces from?
Del: Same place you got them kings. I knew you was cheating, Boycie.
Boycie: Oh yeah? How?
Del: Because that wasn't the hand that I dealt you.

Leverage features a poker game involving this in the episode The Two Horse Job as the team cheats a corrupt horse owner out of the only horse that he had left after burning down his own stable for the insurance payout.
In Tracker 'Eye of the Storm', Nestov uses his natural alien intelligence to do mathematical analysis and use it to cheat on the game he was playing.
In the episode of Monk where he goes to Vegas, he is able to consistently win at Blackjack at the suspect's casino, despite the dealer using multiple decks. Finally, the suspect declares him a card-counter and has security drag him out. Of course, Monk is naturally this observant, which is the reason why he's such a good detective.

Theater

Guys and Dolls: Big Jule has his own set of dice; he had the numbers taken off of "for luck." Fortunately he remembers where the spots formerly were, so when he rolls he tells people what his point is.

Video Games

In the first Mass Effect game, you have the option of helping a Salarian develop a cheating module for Quasar. Of course, cheating is illegal, so he has no intention of using it himself, just selling it to others.

Western Animation

In Futurama, Bender is an inveterate gambler, and he has no compunction against cheating. Hell, he even has a cheating unit, though it's prone to malfunction. He's fixed horse races, used x-ray specs, stacked decks...
- Of course he is still in idiot. He once gave away that fact that he used X-Ray specs by revealing that a player had an internal problem.