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.

PingPongPlus (PP+) is a digitally enhanced version of the classic ping-pong game. We have designed a digital layer of audio/visual augmentation on top of a conventional pingpong table using a newly developed ball tracking system and video projection. The "reactive table" displays patterns of light and shadow as a game is played, and the rhythm and style of play drives accompanying sound. In the process, this project explores new ways to couple athletic recreation and social interaction with engaging digital enhancements. This paper describes the basic idea, research agenda, several applications, technical implementation, and initial experiences. Keywords augmented reality, reactive surface, athletic / kinesthetic interaction, computer-supported collaborative play, interactive media art.