This paper introduces a novel interface for digitallyaugmented cooperative play. We present the concept of the "athletic-tangible interface," a new class of interaction which uses tangible objects and full-body motion in physical spaces with digital augmentation. We detail the implementation of PingPongPlus, a "reactive ping-pong table", which features a novel sound-based ball tracking technology. The game is augmented and transformed with dynamic graphics and sound, determined by the position of impact, and the rhythm and style of play. A variety of different modes of play and initial experiences with PingPongPlus are also described. Keywords tangible interface, enhanced reality, augmented reality, interactive surface, athletic interaction, kinesthetic interaction, computer-supported cooperative play.