The 3,500-hour commercial pilot, who was exercising sport pilot privileges, lost control of the tailwheel-equipped airplane upon encountering the jet blast from a twin-turbofan powered corporate jet. The airplane was taxiing to the ramp upon completion of a local flight when the mishap occurred. The corporate jet was being run-up by maintenance personnel with the jet engine blast directed across the taxiway. The single-engine airplane came to rest in an upright position and the pilot and passenger were able to exit the airplane unassisted. The left wing spar was found to have received structural damage. The airport did not have an operating control tower. According to the Aeronautical Information Manual, Chapter 7, paragraph 7-3-8 a, "....the flight disciplines necessary to ensure vortex avoidance during VFR operations must be exercised by the pilot." In addition, paragraph 7-3-1 states that "pilots of larger aircraft should be particularly careful to consider the effects of their 'jet blast' on other aircraft....during ground operations."