The pilot reported that while taxiing from a grass tiedown area, the airplane’s left wingtip struck the propeller of a parked airplane. She did not notice the wingtip strike, so she continued to taxi and obtained her instrument flight rules (IFR) clearance. After transitioning to the paved taxiway yellow centerline stripe, the airplane’s right wing tip struck the propeller of a second parked airplane. The pilot shut down the engine and exited the airplane to examine the damage. The airplane sustained minor damage to both wings. The incident occurred during the annual Experimental Aircraft Association AirVenture fly-in. The airport issued a Notice to Air Mission that was active at the time of the incident that advised operators “FBO RAMP, T HANGER RAMP PRKG NOT STD.” The pilot stated that it was not clear to her what this meant. The pilot recommended that additional personnel for wing walkers could have prevented the incident. According to the Aeronautical Information Manual, being centered on the taxiway centerline does not guarantee wingtip clearance with other aircraft or other objects.