To throw a curve in dodge ball, you must hold your ball between your hand and position yourself in a certain angle. Your body must be perpendicular to your target. Move back your hand and then bring it forward in a sidearm sweeping motion. You will then let go of the ball and let it roll off your fingertips to create spin. Check out http://entertainmentguide.local.com/curve-dodgeball-6982.html for more details.