Two airplanes were taxiing when a ground collision occurred. According to the pilot of the Cessna 172, he was taxiing towards the run-up area, when he saw the engine start of a Cessna 150. He said it was stationary in a parking spot facing the taxiway as he proceeded forward. As he continued to taxi, he saw the right wing of the Cessna 150 pass under his wing toward his airplane. As he tried to avoid a collision, the right wing tip collided with the windscreen. During the collision the right aileron of the Cessna 150 sustained substantial damage. According to the pilot of the Cessna 150, he was preparing to exit the ramp area and taxi to runway 08. After making a radio call, he checked the taxiway for other aircraft, and said his sight was limited due to an airplane that was parked next to him. He said that he checked to see if any airplanes were on the taxiway and did not see any. He pulled out onto the taxiway and felt a slight bump when the Cessna 172 struck his airplane from behind. Both pilots reported no preimpact mechanical malfunctions or failures with the airplanes that would have precluded normal operation.