At about 1510 Pacific time, a taxiing Cessna 172N collided on the ground with a standing Cessna 172P. The Private pilot and one passenger in the taxiing Cessna 172N were not injured; the airplane sustained minor damage. The CFI, the Student pilot, and one passenger in the standing Cessna 172P were not injured; the airplane sustained substantial damage. Both aircraft were preparing to depart. Visual conditions prevailed. The Cessna 172Ns pilot subsequently stated that, while attempting to taxi around a stationary airplane in a crowded run-up area, he took his eyes off the wing area, and the wing tip of his airplane collided with the other airplanes rudder and vertical stabilizer.