Most versions of the game can be played by up to three players. The game can be played by only one player on the website and the iOS app. The game can be played by up to four players on the tabletop version, You Don't Know Jack 2011 (except for the PC, WebTV, and Nintendo DS versions, which are limited to two players), the OUYA version, Party and the game in The Jackbox Party Pack titled You Don't Know Jack 2015. The Full Stream edition in The Jackbox Party Pack 5 can accommodate up to eight players plus up to 10,000 additional "Audience" members. All versions of the game feature the voice of an off-screen host, who reads questions aloud, provides instructions regarding special question types, and pokes fun at the players.
The game usually opens with a green room segment, in which the players are prompted to enter their names and given instructions for play. The audio during this segment includes rehearsing singers, a busy producer, and a harassed studio manager/host. The only graphics are a large "On Air/Stand By" sign in the middle of the screen, visual representations of the players' button assignments, and a box for name entry. If the players take too long to think of their names or if the players press the "return" or "enter" key without typing in their names, then the announcer will name the players.
In games starting with the Netshow, on certain days, such as Christmas Eve, or certain times such as a Saturday night, or even during Twilight, the announcer will mention the time of day or the special holiday, and sometimes grumble about the game being played at that time or on that day. There is no box for name entry in the second episode of The Ride. In the PlayStation versions, after the game is finished, players can name themselves next to the score recorded. In the console versions of You Don't Know Jack 2011, the OUYA version, and the single-player games of You Don't Know Jack 2015, the players are prompted to choose their names that they typed in before starting the game. (The console versions of You Don't Know Jack 2011 also allows players to make new names in the "Contestants" section.)
If one or more players choose the "I don't care" option, the announcer or the host will tell that they refused to enter their names. Additionally in these games, the sign-in screen is famous for an Easter egg where if the player types in the phrase "fuck you" as their name. The phrase will be changed to a good name afterwards. In You Don't Know Jack 2011 and OUYA, the announcer will tell the player that they have no friends or didn't use proper English.
In You Don't Know Jack 2015, the host will punish the player for typing the offending name. If the player does it once, the host will deduct $1,000 from their score. If the player does it again, the host will deduct $50,001 from their score. (The deduction is only cinematic, and does not persist to the first question of the game.) If the player does it three or more times, the host will end the game with a goat, forcing the player to return to the main menu of the game.
Most versions of You Don't Know Jack offer the choice of playing a 7- or 21-question game; some versions offer only 15 questions (the Netshow, Louder! Faster! Funnier!, 5th Dementia and Mock 2), and others offer only 13 questions (The Ride), 11 questions (HeadRush, You Don't Know Jack 2011, iOS, OUYA, Party, You Don't Know Jack 2015 and Full Stream), or 7 questions ("The Lost Gold" and the Flash website). In a 21-question game, there is a brief intermission after the tenth question. Most questions are multiple choice, with some occasional free-entry questions, or mini-games. The Facebook version offers only 5 questions.
In its original format (Vol. 1, Sports, Vol. 2, Movies, TV, Vol 3, HeadRush, Offline, Louder! Faster! Funnier! and "The Lost Gold"), before each question, one player is given a choice of three categories. Each has a humorous title that has some connection to the topic of the corresponding question. After a short animated introduction, which is often followed by a sung jingle about the question number, the host asks the question. Typically, the question is multiple choice and players are given 10 seconds to select an answer. The first player to "buzz in" and give the correct answer wins the money for that question and gets to choose the next category.
If a player answers incorrectly, they lose money, but not before the host wisecracks about it. If all players answer incorrectly, or if none of the players buzz in and answer the question before the timer runs out, the host will reveal the correct answer; failing to answer doesn't affect a player's score, the host will then randomly choose a player to select another category. In The Ride, 5th Dementia, Mock 2, the website, You Don't Know Jack 2011, iOS, the Facebook version, OUYA, Party, You Don't Know Jack 2015 and Full Stream, the category is chosen by the host or pre-assigned to an episode.
