A ball game to be played in a swimming pool and a tilted backstop for use in the ball game. The backstop, includes a rigid broad board; and a supporting apparatus for supporting the board in a position that is tilted from the vertical at an angle in a range of ten degrees to twenty degrees when the supporting apparatus is placed upon a horizontal surface. The supporting apparatus includes a pair of rods extending horizontally from the bottom of the board in the direction that the top of the board is tilted forward. The forward ends of the rods are bent downward for hooking over the edge of a curb for preventing the board from being thrust backward when the forward broad surface of the board is struck. The backstop is positioned on a horizontal surface against a curb at the edge of a swimming pool so that the forward ends of the rods hook over the edge of the curb. A first person positioned in the swimming pool throws a ball to strike the forward board surface of the board so as to rebound from the board either directly toward the pool or onto the horizontal surface at the top of the curb and thence toward the pool. A second person positioned in the pool tries to catch the ball. Scoring of the game is determined by whether or not the ball is caught and how far it rebounds from the board if it isn't caught.