Infinite Challenge (a.k.a. Muhan Dojeon; Hangul: 무한도전; hanja: 無限挑戰; abbreviated as 무도 Mudo) is a Korean television entertainment program, distributed and syndicated by MBC. As of January 2013, it still has the largest market share for its timeslot; roughly between 13 to 17 percent of Korean television viewers watch Infinite Challenge at 6:30 PM every Saturday night. This makes it the top free-to-air television program on Saturday evening, and it's also the most viewed non-drama program in South Korea every week (excluding special sporting events, since November 2006, with the exception of January 2009, April and May 2010). It has kept the same scheduled time, since first airing in 2005. Since 2009, it lasts for roughly 75 minutes, excluding ten minutes of advertising. Episodes are also frequently rerun on several Korean cable broadcasting channels. Since February 19, 2011 (episode 237), the program has been aired in high-definition. Infinite Challenge have been called the nation's variety and Korea's real first variety for having been successful for over nine years.
Infinite Challenge is recognized as the first "Real-Variety" show in Korean television history. The program is largely unscripted and follows a similar format of challenge-based Reality Television programs, familiar to some audiences in the West. The challenges are often silly, absurd, or impossible to achieve, so the program takes on the aspect of a satirical comedy variety show rather than a more standard reality or contest program. In earlier episodes, the show's six hosts and staff would continuously proclaim that, in order to achieve its comedic purposes, the program was 3-D: Dirty, Dangerous, and Difficult.