At 1722 central time, a Piper PA-18-150 lost power while towing a banner and was damaged in the ensuing forced landing. The pilot was not injured. The pilot was flying at 1,000 feet on the right tank, which indicated full, when he was distracted by radio communications with other banner tows. The engine quit and the pilot switched to the left tank, which was full, but could not restart the engine. Prior to the airplanes forced landing, the banner got tangled in trees and wires.