The pilot reported that after takeoff, about 250 feet above ground level (agl), the engine "suddenly cut out." He reduced the throttle to idle and attempted to land on the runway; however, there was not enough distance remaining. He subsequently pushed the throttle forward and the engine regained power. As the airplane reached approximately 250 feet agl, the engine lost power again. The pilot subsequently set up for a forced landing to a harvested corn field immediately west of the airport. The airplane nosed over during the emergency landing. A post accident examination of the engine did not reveal any anomalies consistent with a pre-impact failure or malfunction. The pilot noted that his intention was to stay in the airport traffic pattern in order to practice takeoffs and landings because it had been approximately 6 months since he had flown the airplane.