Turns
Take turns. Decide who goes first (a dice roll works) and let him choose a question. After it's read, allow a period of time (generally 10 seconds) in which any player can "buzz in" and offer an answer. The player has five seconds to answer. If his answer is correct, he takes control of the board and gets to choose the next question. If he is incorrect, he loses his turn. Another player can try to answer and take control. If no one answers correctly, control goes back to the player with the most recent correct answer.
Gaining and Losing Points
Distribute points. Start each player with a score of zero and add points when a player gets an answer right. For an incorrect answer, take points away. The value of the points is determined by the round and difficulty of the question. During the first round, questions range from 100 to 500 points. During the second round, point values are doubled.
Daily Doubles
During the first round, there is one Daily Double. This means the player who chose the question is the only one allowed to answer it. He can bet up to his entire current score (although if his score is less than $1,000, he can still bet $1,000). In the second round, there are two Daily Doubles, which work the same way.
Declaring a Winner
The final round is one Final Jeopardy question. Each player can bet up to the amount of his current score. If he answers correctly, whatever he bet is added to his score for a final total. If he loses, the bet is subtracted. The person with the highest score wins.
The Form of a Question
Some people like to play Jeopardy the way it is on TV, in which all answers must be in the form of a question--the idea being that the questions themselves are actually "answers." For instance, if the "question" on the board were: "This man was U.S. president in 1980," the answer would be: "Who is Ronald Reagan?" Other players simply allow the answer to be given (e.g., "Ronald Reagan").