The pilot reported that he had performed two touch-and-go takeoffs and landings without incident. On the third landing, he noted the wind was straight down the runway. After touchdown, the pilot added power and raised the flaps for takeoff. Within a few seconds the airplane veered sharply to the left and he attempted to correct back to the runway. He observed taxiway lights and a large sign on his right side. The pilot stated that he did not want to damage the airplane by making an abrupt maneuver toward the runway, so he steered the airplane to the left and away from the sign; however, the tail section struck the sign. The airplane departed the runway and came to a stop in the field. Post-accident examination of the airplane revealed that the elevator had sustained substantial damage. The pilot reported no mechanical anomalies with the airplane at the time of the accident.