Take a boat out to Koh Phangan overnight especially if you are close to a full moon day as there will be a great beach party that is known all over Thailand. If you head out earlier in the day, you can make it a complete trip where you take a tour of the secret beaches, the jungle-covered mountains and massive rocky peaks of Koh Phangan. After which you can spend the sunset and the rest of the night dancing away at the Moon Festival.