CNN  —  “Place your order.” In the time it took you to read that sentence, another deck of Uno was sold. The family-favorite card game has been around for 52 years — but it may be more popular than ever. Almost everyone seems to play it, and by one measure it’s the top-selling game in the world. Almost one set of Uno was sold in the US every second last year, according to Mattel, its publisher. That’s almost 60 Uno decks each minute — up from 17 sets each minute in 2021. Its popularity is due to the game’s broad appeal, says Michelle Parnett-Dwyer, a curator at the Strong National Museum of Play in Rochester, New York. “Kids can play against adults without being overmatched, and adults can play it together and still have fun,” she says. “The gameplay is simple and easy to understand, and playing a round moves quickly.” More than 600 editions of Uno are available, but the game’s core mechanics remain mostly the same with each new version. Players draw a handful of cards and then take turns trying to discard them; the first player to get rid of all their cards wins. Morgan Coder, left, plays Uno with Kathleen Stoughton, 64, center, and Kathleen's husband Kim, 61, at a cooling center in Portland, Oregon in 2021. Alisha Jucevic/For The Washington Post/Getty Images A player can put down a card if it matches either the color or number of the previous card at the top of the play pile. Or to switch things up, players can put down an action card — requiring the next player to draw more cards or skip a turn. Uno makes frequent cameos in popular culture. The Obama family played the game together as far back as 2007. The game has appeared in many celebrities’ social media posts, from Joe Jonas to Kylie Jenner. John Legend and Chrissy Teigen once brought Uno to Vanity Fair’s Oscars viewing party. And last July, Questlove threw a star-studded Uno party attended by Taylor Swift and Jason Sudeikis. The game was recently featured in an episode of the TV series “Hacks,” when lead character Deborah Vance joins some old friends for a card game in Las Vegas, only to learn that instead of poker they’re playing Uno. In 2021, Mattel announced it was creating a live-action heist comedy movie based on Uno, starring rapper Lil Yachty. The shelf life of Uno Uno was created in 1971 by Merle Robbins, a barber from Ohio. Robbins and his wife printed 5,000 copies of the game and traveled around the US selling them at campgrounds. It grew in popularity in the 1980s after the Robbinses sold the rights to the game. And then, in 1992, Mattel acquired it. Uno, it seems, is one of those games that has remained popular through multiple generations. It’s often there in the background in people’s homes — stacked on a shelf with other board and card games or stored in a drawer, ready for game nights and camping trips. The game is “relatively inexpensive and portable,” says Parnett-Dwyer. The cheapest versions go for under $6 on Amazon. This makes it easy to replace a “well-loved version (that) has one too many creases and bent edges” with a new deck, she says. Uno currently holds the top spot in the traditional games category — which includes everything you would find in the games aisle at a Walmart or Target, including board games (with the exception of trading card games such as Pokémon and Yu-Gi-Oh!) — according to retail tracking service Circana. It has held this title for two years globally, and three in the US. The card game is now for sale in over 80 countries. Its many editions range from a braille Uno to a nonpartisan edition, where the usual red and blue cards are swapped for orange and purple to avoid associations with American politics. There are many variations of Uno, including this braille edition. Daniel Karmann/dpa/picture alliance/AP This year alone, Mattel has released 27 new Uno decks. These includes the launch of Uno Fandom, a category that “celebrates fandoms big and small across TV, film, sports teams and pop culture,” Mattel’s Vice President and Global Head of Games, Ray Adler, tells CNN. These decks, commemorating everything from Harry Potter to the NFL, include special rules and collectible foil cards. “The original Uno has staying power because of its broad appeal,” says Parnett-Dwyer. “But different editions and variations have certainly helped with attracting new audiences and getting kids excited about playing their first round.” How new versions of Uno factor into the game’s popularity Mattel has seen over a long period of time that these new Uno versions are “additive and non-cannibalistic,” says Adler, meaning the fresh editions contribute to the game’s overall growth and do not hurt sales of existing products. In one of its biggest departures from the traditional playstyle of Uno, Mattel released a version called Show ‘em No Mercy in October 2023. It quickly sold out, and Mattel continues to struggle to meet demand, Adler says. Show ‘em No Mercy is an extreme edition of the game and comes with a slew of new rules and new cards (an additional 56 on top of the 108 in the traditional game). This includes a “Draw 10” card and a rule that once you reach 25 cards in your hand you’re out. It also allows stacking, a move in which a player can put down multiple cards — yes, even Draw 10s. Stacking is a hot Uno topic that has led to many debates, both online and during real-life game nights, for not being an official rule. It’s only addressed in the rulebooks of a few versions, such as Uno Attack Mega Hit. Show 'em No Mercy, one of the newest versions of Uno, has a slew of new rules and cards. Courtesy Mattel Show ‘em No Mercy was, in part, inspired by consumer insight and social media feedback, says Adler. “People love playing action cards against their friends and family — and those get some of the best reactions, especially when there are lots of action cards,” Adler says. “And so we said, ‘What if we just took that and went to the next level?’ … the design team did an incredible job of really saying, ‘What are the brutal elements of Uno, and how do you accentuate them?’” Show ‘em No Mercy has resonated with players and gone viral on social media due to its cutthroat play. (Mattel itself has leaned into the social media banter, posting a fake Draw 100 card on April Fool’s Day.) In the first quarter of 2024, it was the second-most popular game in Circana’s traditional games category, right behind traditional Uno. By the end of 2024, Mattel will release “well over” 50 new editions of Uno, Adler says. Most of these will be variants, with only two or three each year having significant changes to gameplay. Parnett-Dwyer says the game was inducted into her museum’s National Toy Hall of Fame in 2018. “Great toys and games get passed on from generation to generation. Many of today’s grandparents played Uno with their kids, and then those next parents play it now with their kids,” she says. “It’s truly a ‘classic.’”