According to the pilot, the start up and run up were normal. After attaining 65 knots during the takeoff roll, the pilot raised the tail and the airplane started to "track hard right" and the left landing gear tire struck a taxiway sign. The taxiway sign broke off and punctured the fuselage skin and struck the horizontal stabilizer. The pilot returned to the airport, and landed without further incident. In the pilot's written statement he indicated that he had not briefed the forward right seat passenger to remain clear of all flight controls, and that he did not retract the right side rudder pedals. He surmised that the right seat passenger inadvertently applied pressure to the right toe brake. The pilot further stated that in the future he will incorporate that into his briefing (to remain clear of the flight controls), and to retract the right side rudder pedals. This event was upgraded to an accident on October 1, 2010, by the Federal Aviation Administration (FAA) after an inspection discovered structural damage to the left landing gear attach box and the leading edge of the right horizontal stabilizer.