In one embodiment a method of operating a mobile device includes sensing either an orientation or a movement of the mobile device, determining a command based on the sensed orientation or sensed movement, sensing a proximity of an object in relation to at least a portion of the mobile device, and executing the command upon the proximity of the object being sensed. In another embodiment, a method of operating a mobile device governs a manner of interaction of the mobile device relative to one or more other mobile devices. In at least some embodiments, at least one of the mobile devices includes an accelerometer and an infrared proximity sensor, and operation of the mobile device is determined based upon signals from those components.