WHILE ATTEMPTING A LANDING ON A GRASS RUNWAY, THE AIRCRAFT BOUNCED AND PORPOISED TO THE LEFT SIDE OF THE RUNWAY. THE PILOT THEN ABORTED THE LANDING BY APPLYING FULL POWER; HOWEVER, THE AIRPLANE PROCEEDED OFF THE RIGHT SIDE OF THE RUNWAY UNDER FULL POWER, WHERE THE LANDING GEAR BECAME ENTANGLED IN LONG WEEDS AND THE AIRPLANE NOSED OVER.