We introduce FlowMouse, a computer vision-based pointing device and gesture input system. FlowMouse uses optical flow techniques to model the motion of the hand and a capacitive touch sensor to enable and disable interaction. By using optical flow rather than a more traditional tracking based method, FlowMouse is exceptionally robust, simple in design, and offers opportunities for fluid gesture-based interaction that go well beyond merely emulating pointing devices such as the mouse. We present a Fitts law study examining pointing performance, and discuss applications of the optical flow field for gesture input.