1. A computer-implemented method performed in connection with a computerized system comprising a processing unit, a camera and a memory, the computer-implemented method comprising: a. using the camera to acquire a plurality of images of a mobile computing device held by a user, the mobile computing device displaying a marker pattern; b. using the central processing unit to detect the marker pattern within the acquired plurality of images; c. using the central processing unit to determine a plurality of positions of the mobile computing device based on the detected marker pattern within the acquired plurality of images; and d. processing a user event based on the determined plurality of positions of the mobile computing device.