Apple's US application 20100279768 on interactive gaming

First claim:

A computer-implemented method performed by a first interactive game device operating in a real world, interactive game environment with a second interactive game device, comprising:

receiving state information from the second interactive game device, the state information associated with a reference frame defining a virtual interactive game environment; and
determining an interaction between the first interactive game device and the second interactive game device in the real world, interactive game environment using the state information.

From the "Background" section:

Modern mobile devices integrate a variety of communication technologies with geopositioning technology and sensors. The communication technologies (e.g., cellular, Wi-Fi, Bluetooth) allow users to communicate with other users in a variety of operating environments. Geopositioning technologies allow users to receive detailed digital maps and location-based services. Various sensors integrated in the mobile device receive input from the operating environment and provide output for a variety of interesting and useful applications running on the mobile device. For example, an accelerometer can detect when a device is held in portrait or landscape orientation, and then adjust a user interface based on the detected orientation. Sensors, such as the accelerometer in Apple Inc.'s iPhone.TM. have also been used in games. The user manipulates the iPhone.TM. in response to game action, such as trying to guide a virtual ball through a virtual maze or steer a virtual car or boat through a virtual racetrack.