Twenty-One (1956)

Two contestants were placed in separate isolation booths. Each player in turn would be given a category and asked how many points, from 1 to 11, he wanted to risk. Points increased with the questions difficulty. A correct answer earned the stated number of points, whereas a wrong answer would result in the points being deducted from the player's score. The first player to get 21 points won, unless the other player matched the score and forced a tie. Players could also end the game early if they felt they had enough points to win.