This paper makes the case for designing interactive robots with their expressive movement in mind. As people are highly sensitive to physical movement and spatiotemporal affordances, well-designed robot motion can communicate, engage, and offer dynamic possibilities beyond the machines' surface appearance or pragmatic motion paths. We present techniques for movement centric design, including character animation sketches, video prototyping, interactive movement explorations, Wizard of Oz studies, and skeletal prototypes. To illustrate our design approach, we discuss four case studies: a social head for a robotic musician, a robotic speaker dock listening companion, a desktop telepresence robot, and a service robot performing assistive and communicative tasks. We then relate our approach to the design of non-anthropomorphic robots and robotic objects, a design strategy that could facilitate the feasibility of realworld human-robot interaction.