Even the ones that look no different from legitimate businesses could actually be a way for the operators to get their victims Trapped by Gambling Debts and threaten financial ruin if they don't do dangerous or illegal things for them. Compare the Loan Shark in this case.
Often found in a Friendly Local Chinatown, and may overlap with a Legitimate Businessmen's Social Club. Also a common source of income for organized crime such as the Yakuza, The Mafia, and other Generic Ethnic Crime Gangs.
- Molly Bloom of Molly's Game organizes illegal poker games after her skiing career flounders because of a Career-Ending Injury. Based on a True Story.
- In flashback in The Mountie, Sergeant Greyling is shown breaking up an illegal gambling den that stages dog fights.
- One run in the back room of a Chinese takeout restaurant in the majority-Black Crenshaw district appears in Rush Hour 2. Detective Carter knows the proprietor and looks the other way regarding the illegal gambling operations in exchange for leads on a counterfeiting ring he and Detective Lee were tracking — turns out one of the regulars at the den had used the counterfeit notes to play earlier.
- In Bones, one victim uncovered a dog-fighting ring. He was killed because the operator found out he was gathering evidence against them.
- Showed up in a few episodes of Dragnet, usually as an illegal bookmaking operation or a "floating" poker game that Friday and Gannon had to bust while working in Administrative Vice.
- Motive: In "The Amateurs", the Victim of the Week is Ken Leung, the deputy leader of the ruthless Golden Tiger Triad, the largest criminal organization in the city. The triad makes money in part through their illegal mahjong gambling den.
- In NUMB3RS, the team uncovered a gambling website where patrons can bet on a deadly version of Russian Roulette.
- Riverdale: Being deeply in debt to her father, Gladys Jones and the bank in season three, Veronica Lodge temporarily opens one at her club La Bonne Nuit, hoping to make enough to pay off her debts. Unfortunately her acquaintance Elio (the son of New York Mob Boss) keeps cleaning up forcing her into even more debt, until Hiram takes her aside to reveal Elio's cheating in an attempt to make the Lodges look weak. Together they conspired to beat Elio in one really big game, thus winning her money back.
- The Tick: A minor plot point in season two is that there is a gambling den running in The City, requiring a thousand dollars for entry, which is utilised by major criminals and also the retired hero Flexon. Arthur goes undercover as shady character "the accountant" to get information on the a gang of bank robbers the Donnelley Brothers, even ending up playing poker with their leader. The entire operation is shut down by Ms. Lint, posing as a hero called Joan of Arc so she can take out her rivals with immunity.
- An episode of Wonder Woman featured one of these hidden behind a video arcade.
- The Marvelous Mrs. Maisel: In season 3, Joel's new club in Chinatown happens to be over an existing illegal gambling den that operates out of the basement. Anytime Joel has to go downstairs because they're making a ruckus, they'll always instantly cease everything they're doing...then go right back to it as soon as he disappears upstairs.
- Luke Cage (2016): Cockroach Hamilton in season 2 runs an off-the-books casino in a Harlem warehouse, in light of getting out after his last conviction was found to have been tainted by the late Detective Scarfe.
- Carlo Rizzi in The Godfather has been given one of the "looks legit" variety to manage by the Corleone family. Since illegal gambling is one of their profit centers, it's a test of whether he would be competent enough to be given more responsibilities. He isn't. One day he gets the odds wrong on sports betting so gamblers win more than they risk. Afterwards, a more trusted Corleone member is always kept on-scene to make sure he doesn't screw up again.
- Blades in the Dark: There is a bunch of illegal gambling dens scattered throughout Duskwall. In gameplay terms, these locations have two purposes: for Scoundrels with a Gambling vice, they can serve as places to reduce stress (a gameplay mechanic), while for some types of crews, they are available as claims that generate coin after every score.
- Guys and Dolls features "the oldest established permanent floating crap game in New York." The "floating" adjective is because it constantly seeks out new venues after its old venues get locked down or raided by cops.
- In Sleeping Dogs, you can find gambling dens on offshore oil rigs.
- In Way of the Samurai 4, there is a Yakuza-run gambling den in the outskirts of Amihama, where the nameless ronin can play Koi-Koi at night. The place also offers free sake to those who take the sidequests that the gambling den mistress issues.
- Pokémon Red and Blue has an example which gets apparent through subtext. The game corner in Celadon city is run by Team Rocket (basically the Japanese Yakuza), and to claim your prizes you must go to a building next door. It's set up this way to circumvent Japanese law: casinos are illegal in Japan, but as long as the prizes aren't handed out in the same building, the parlor can claim they only offer skill games. The game corner also doubles as a front for Team Rocket's base of operations located in the basement.
- While chasing down walking John Woo reference Fat Chow, the protagonist Jack from Dead to Rights walks into one such place, and invokes the trope word for word to get everybody's attention.
- A regular feature in Yakuza games, where the gambling dens are primarily run by homeless people. There's also an underground pleasure district called Purgatory that includes a casino.
- Bob's Burgers: In "The Kids Run the Restaurant", the Belcher kids start an underground casino in the basement of the restaurant while Linda is taking Bob to the hospital to get a nasty cut stitched up.
- Parodied in Fillmore!, where the school safety patrol infiltrates an illegal "smoit" (basically box-tops) casino.
- There are a lot of Mafia-operated bookies where the Mafia loves getting people Trapped by Gambling Debts to get their hooks into indebted businesses. In fact, most wannabe mobsters started out their careers as bookmakers or errand boys for veteran mafiosi, and the American Mafia itself started out as numbers-running operations.
- The Yakuza is theorized to have started out as guilds of street peddlers who ran illegal gambling rings, as "ya-ku-za" (893) is the worst possible hand in the Japanese card game oicho-kabu.
- The Wah Mee club in Seattle started as a legitimate nightclub, but fell on hard times and became this. It culminated in three men setting up a violent armed robbery where they planned to kill everyone inside and take all the money they could grab (as it was an illegal operation, everything was cash-only). It ended with thirteen dead and a Sole Survivor (one of the club's dealers, who identified the robbers).
- Molly Bloom ran illegal poker games for show business major figures until the FBI got her.