The pilot obtained glider tow/support services from Sylvania Soaring Adventure, Inc. at the departure airport for a local flight. While returning to the departure airport, the pilot provided radio transmissions announcing the airplane's position on downwind, base, and final segments of the visual approach to runway 07 (3,200 feet by 50 feet, asphalt). Upon touchdown, a member of the support service ground crew crossed the runway in a golf cart at about a 30 degree angle. The pilot turned the glider to avoid hitting the golf cart but the glider hit the golf cart with its left wing. The glider sustained substantial damage that included a cracked and delaminated left wing. The pilot and golf cart driver were uninjured. The golf cart was not equipped with a radio to monitor and provide information to airport traffic. Following the accident, Sylvania Soaring Adventure, Inc., has adopted the following procedures: use of radios by golf cart drivers while operating on airport movement areas, golf cart drivers are to stop and look both ways prior to crossing runways, and runways are no longer to be crossed at angles less than 90 degrees.