Abstract: A game ball has a first hemisphere provided with depressions or protrusions which constitute from 1% to 30% of the surface of the hemisphere, the depressions being located solely in the middle one-third annulus of the hemisphere. When projected along the plane of a line joining the first hemisphere and a second hemisphere, the ball will deviate from a normal trajectory in the direction of the one hemisphere. The second hemisphere may have a smooth surface, or may have a uniform texture, such as that found on a tennis ball.