The glider pilot reported that, while being towed the glider began to climb and the canopy opened. The pilot released the glider from the tow airplane, and he reached up and closed the canopy. He recalled that he decreased the glider's airspeed, and he made a 180° right turn to final. On final, the glider was high, and he deployed the airbrakes, but the canopy opened again. The pilot closed the canopy and held it shut with his left hand, while trying to control the glider with his right hand, but the glider's altitude decreased "very quickly." The glider's wingtip struck a shipping container that was just short of the runway. The glider sustained substantial damage to the left wing and the empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation.