In this paper, we present the Gesture Cube, a digitally augmented cube for human-computer interaction. The Gesture Cube is designed to be an unobtrusive and playful interaction device for controlling media appliances. Additionally, we discuss in more general the development process for gesture input. In an explorative user study, we analyzed user requirements, and in particular we were interested in the set of meaningful gestures that users think of. Based on this, a digitally augmented cube for controlling home appliances and computer applications was designed. Gestures are used as the main form of input for interaction with the system. Two applications are shown, a 3D visualization of the state of the cube and an MP3 player, to illustrate the feasibility of the user interface we used. These applications were evaluated and showed that gesture interfaces can provide a playful and yet efficient means for interaction with everyday devices.