1. An apparatus for modifying computer mouse commands comprising: a USB input connector configured to connect to a computer mouse; a USB host emulator structure coupled to the USB input connector configured to communicate with the computer mouse; a control electronics structure coupled to the USB host emulator structure; a mechanical controls structure coupled to the control electronics structure; wherein the control electronics operate on mouse events to produce modified mouse events based on the position of the mechanical controls; wherein the production of modified mouse events is performed in real time in response to user input to the mouse; wherein the mechanical controls are comprised of knobs and switches; wherein the knobs modify at least the frequency of the mouse events; a USB slave emulator structure coupled to the control electronics structure configured to communicate with a host computer; a USB output connector configured to connect to the host computer; and a housing to couple to the USB input connector, the mechanical controls and the USB output connector.