By computationally facilitating throwing and catching interaction, our approach can be applied in many applications including kinesthetic learning, gaming, immersive haptic experience, ceiling storage, and communication. We demonstrate the applications with a proof-of-concept system enabled by wheeled robots, ceiling hardware design, and software control. Overall, ThrowIO opens up novel spatial, dynamic, and tangible interaction for users via overhanging robots, which has great potential to be integrated into our everyday space.