The pilot of the Mooney M20F retracted his landing gear almost immediately after the tires lifted off the runway. He continued to accelerate while flying very low over the airfield, and then executed a steep right hand 180 degree turning pull-up. Numerous pilot-rated witnesses stated that during this pull-up the aircraft appeared to be flying just on the edge of a stall. He then proceeded to the approach end of the airfield, entered a descending turn and then executed a high speed, low level pass. During this pass a helium filled balloon was released for the pilot to attempt to burst with the aircraft's propeller. At the conclusion of this pass, the pilot made a rapid climbing pull-up to the left, reaching an altitude of approximately 300 feet above ground level. The bank angle at the top of the climbing turn was estimated by the witnesses to be approximately 50 degrees. The aircraft maintained approximately the same angle of bank as it descended toward the terrain, ultimately impacting near the runway.