Since the revival of Jeopardy! in 1984, the Jeopardy! brand has been used on products in various other formats.
Jeopardy! has been adapted into several different versions of video games. Most versions released prior to 1998 were published by GameTek, which folded later that year.
A version for the Nintendo Entertainment System first appeared in 1987, which supports up to three players (but not the NES Four Score accessory). Three modes of difficulty are available – easy, normal, and hard – with the amount of time allotted to give the correct question decreasing as the difficulty level increases. Because of the time period in which the game was released, the clues deal mostly with events of the 1980s based on issues in the United States.
Three contestants take their place behind three lecterns; each equipped with a hand-held signaling device, and a screen with a light pen. During non-tournament games, the returning champion occupies the leftmost lectern from the viewer's perspective. The contestants compete in a quiz game comprising three rounds—Jeopardy!, Double Jeopardy!, and Final Jeopardy!. The material for the questions covers a wide variety of topics (including history and current events, the sciences, the arts, popular culture, literature, and languages), and there are pun-laden titles (many of which refer to the standard subjects), wordplay categories, and even entire sets of categories with a common theme.
The Jeopardy! and Double Jeopardy! rounds each feature six categories which each contain a column of five clues (phrased in answer form), each clue incrementally valued more than the previous, ostensibly by difficulty. The value of each clue within categories has changed over time: on the original Jeopardy! series, the Jeopardy! round clue values ranged from $10 to $50 in increments of $10; on The All-New Jeopardy!, they ranged from $25 to $125 in $25 increments; on the daily syndicated version, the Jeopardy! round clue values originally ranged from $100 to $500 in increments of $100, but were doubled on the episode aired November 26, 2001; and on the Super Jeopardy! specials, where clue values were in points rather than in dollars, the Jeopardy! round clue values ranged from 200 to 1,000 points in 200-point increments.
The contestant at the leftmost lectern from the viewer's perspective selects the first clue in the Jeopardy! round from any position on the game board. The selected clue is revealed and read by the host, after which any of the three contestants may ring-in using a hand-held signaling device. The first contestant to ring-in successfully after the host has read the clue must then provide a response phrased in the form of a question; for example, if a contestant were to select "Presidents for $200", the resulting clue could be "The Father of Our Country, he didn't really chop down a cherry tree", to which the contestant's response should be "Who is George Washington?" A correct response adds the dollar value of the clue to the contestant's score and gives them the opportunity to select the next clue from the board. An incorrect response, or a failure to respond within a time limit of five seconds (signified by the red lights on the contestant's lectern), deducts the dollar value of the clue from the contestant's score and gives any remaining opponent(s) the opportunity to ring-in and respond. If none of the contestants give a correct response, the host reads the correct response and the contestant who selected the previous clue chooses the next clue.
Contestants must wait until the host finishes reading the clue before ringing in; doing so before this point locks the contestant out for one-fourth of a second. Originally, contestants were allowed to ring-in at any time after the clue had been revealed, but that rule was changed when the Trebek version's second season premiered in 1985, both to allow home viewers to play along more easily and to decrease the likelihood of faster contestants dominating the game. Pre-1985 Jeopardy! episodes featured a buzzer that would sound whenever someone rang in; according to Trebek, the buzzer was silenced because it was "distracting to the viewers" and sometimes presented problems with contestants inadvertently ringing-in too soon to allow him to read the clues in their entirety.
The Double Jeopardy! round, as its name implies, features clue values that are exactly double those of the Jeopardy! round clue values (except during Super Jeopardy!, in which the clue values ranged from 500-2500 points in 500-point increments). The contestant with the lowest amount of money at the end of the Jeopardy! round makes the first selection in Double Jeopardy! If there is a tie for second place or a three-way tie for first place, the contestant with the tied score standing at the leftmost lectern selects first. Contestants who finish Double Jeopardy! with $0 or a negative score are automatically eliminated from the game before Final Jeopardy! and awarded the third place prize. On at least one episode hosted by Fleming, all three contestants finished Double Jeopardy! with $0 or less, and, as a result, no Final Jeopardy! round was played that day; so far, there has not been an episode of the Trebek version where all three contestants finished Double Jeopardy! with $0 or less.
One clue hidden on the Jeopardy! round game board, and two on the Double Jeopardy! board, are designated "Daily Doubles", taking their name and inspiration from a horse racing term. Only the contestant who selects a Daily Double may respond to its clue. The contestant must first decide how much to wager, from a minimum of $5 up to a maximum of all of their money (known as a "true Daily Double"), or the highest dollar amount in the round, whichever is greater. The contestant maintains control of the board and the right to select the subsequent clue, regardless of whether or not their response to the Daily Double is correct. Daily Doubles accompanied by audio or video elements are designated with appropriate tags which are displayed before the wager is made.
During the Jeopardy! round, except in response to the Daily Double clue, contestants are not penalized for forgetting to phrase a response in the form of a question, although the host will remind contestants to watch their phrasing on future clues. During the Double Jeopardy! round, and on the Daily Double clue in the Jeopardy! round, adherence to the phrasing rule is followed more strictly, but contestants are still permitted to correct themselves before their time runs out. If it is determined that a response previously given by a contestant was wrongly ruled correct or incorrect, the scores are adjusted at the first available opportunity. If, after a game is over, a ruling change is made that would have significantly altered the outcome of the game, the affected contestant(s) are invited back to compete on a future show.