During the local training flight, the flight instructor simulated a spoiler and altimeter failure while landing. The glider was high and fast and the pilot attempted to lose altitude by performing both side slips and S-turns while on final. The glider overran the runway and impacted trees at the departure end of runway 27 (2,800 feet by 150 feet, turf). The right wing was substantially damaged during the impact with the trees. There were no mechanical anomalies that would have prevented normal operation prior to the accident.