[wilsonmw04]

The compass can tell you your heading from the earth's magnetic field, not a from a magnet on the field of play. My kids were playing with the NXT brick and were able to have the robot point north with just a click of a button. You might be able to have the robot capture it's initial heading at the beginning of the game, and make turns relative to that heading. My only concern with using it is the interference you might be getting from other magnetic fields in the area.