The main game [change]
Two contestants fought against each other in the main game—the returning champion and a challenging contestant. The returning champion was represented by the color red. The challenger was represented by the color blue. The host, Jim Perry, then asked a toss-up question, which was asked to 100 people before the show (example: "We surveyed 100 lawyers: Have you ever defended a person who you believed was guilty? How many lawyers said they have?"). The contestant he asked it to would provide what they thought the number of people who gave the answer the host gave. The other contestant would then say whether they thought the actual number was higher or lower than the first contestant's guess. Whoever is closer to the number got a chance at the cards.
There were two rows of five cards: the top red row (for the champion) and the bottom blue row (for the challenger). The contestant in control had to predict whether each card was higher or lower than the card before it.
There were two games. Whoever won both games would go on to play the Money Cards.
The Money Cards [change]
The winning contestant would then play the Money Cards to win more money. He/she was given $200 to start out with. They then had to predict whether each card was higher or lower than the one before it, just like before. This time, they had to bet money on each guess (example: $200 higher than a 2). The contestant worked their way across the bottom row, in which there were four cards, and then made it to the second row and were given $200 more. The least a person could bet on each card for the first two rows was $50. They then worked their way across that row, until they reached the top row, where there was only one card. That row was called the "Big Bet" row. There, the contestant had to bet at least half of what they won before.
Other versions [change]
Card Sharks aired on NBC from 1978 to 1981 and was hosted by Jim Perry. It returned on CBS and in syndication in 1986. The CBS version was hosted by Bob Eubanks and ran until 1989. The syndicated version was hosted by comedian Bill Rafferty, but ran until 1987.
In 2001, Card Sharks came back, hosted by Pat Bullard. However, this version had different rules than the other ones. In this one, two teams of two contestants (two at a time) had to guess higher or lower (or predict if the next card had exactly the same number as the previous one) on one row of seven cards. This version was not very popular and was cancelled after 13 weeks. Many Card Sharks fans say this version is the worst game show revival of all time.