During a cross country flight, the pilot of the experimental amateur built airplane encountered thunderstorms along his route. This added an additional 45 minutes of unanticipated flight time. He was concerned that night conditions were present, his airplane was not equipped with a landing light, and his destination airport was not lighted; as a result, he decided to divert to another airport which was equipped with lighting and had a longer paved runway. During his first attempt to land at the diversion airport, he was too fast on final approach and elected to go-around. During his second attempt to land, he misjudged his rate of descent and landed hard. The airplane then bounced twice. After the second bounce, he attempted to recover and go-around by adding full power and right rudder but the airplane entered a left roll, struck the ground with its left wingtip, and then cartwheeled, separating the engine before coming to rest inverted. During his egress from the airplane, the pilot received minor injuries. Examination of the airplane revealed that it was substantially damaged.