1. A computing device for depth-based gesture control, the computing device comprising: a display to define a surface normal; a depth sensor to: generate depth sensor data indicative of a depth relative to the display of an input gesture performed by a user of the computing device in front of the display; generate second depth sensor data indicative of a second depth relative to the display of a second input gesture performed by a second user of the computing device in front of the display; and generate third depth sensor data indicative of a third depth relative to the display of a third input gesture performed by the second user of the computing device in front of the display; a gesture recognition module to recognize the input gesture, the second input gesture, and the third input gesture; a depth recognition module to: receive the depth sensor data, the second depth sensor data, and the third depth sensor data from the depth sensor; determine the depth of the input gesture as a function of the depth sensor data; determine the second depth of the second input gesture as a function of the second depth sensor data; determine the third depth of the third input gesture as a function of the third depth sensor data; assign a depth plane to the input gesture as a function of the depth of the input gesture; assign a second depth plane different from the depth plane to the second input gesture as a function of the second depth of the second input gesture; and assign a third depth plane different from the second depth plane to the third input gesture as a function of the third depth of the third input gesture; wherein each depth plane is positioned parallel to the display and intersects the surface normal; and a user command module to: designate the second depth plane as an accessible depth plane for the second user; execute a user interface command based on the input gesture and the assigned depth plane; execute a second user interface command based on the second input gesture and the assigned second depth plane; determine whether the third depth is associated with the accessible depth plane for the second user; and reject the third input gesture in response to a determination that the third depth is not associated with the accessible depth plane for the second user, wherein to execute the second user interface command comprises to: determine whether the second assigned depth plane comprises a secondary virtual touch plane of the computing device; and execute a secondary user interface command in response to a determination that the assigned second depth plane comprises the secondary virtual touch plane, wherein to execute the secondary user interface command comprises to display a contextual command menu on the display.