Float on a calm body of water. Buy a plastic float at a nearby store, and head for your favorite water spot. It could be a lake, pond, stream, or swimming pool. Get a cold drink, load up on suntan lotion so you won't burn, hop on your float, and let go.
Feel the weight of your body being supported by the water. Relax your muscles, let go of any tension you may have, and just drift lazily along, slowly moving through the water without a care in the world. Try not to focus on anything but what comes into your mind naturally. Let your mind go as easily as you let your body go. When you close your eyes, imagine yourself gently floating in space.
Make sure you stay on your float long enough to feel that you've been on a voyage, that you've gone somewhere far away and that you have to return. See yourself as a traveler through time.
— Alan Epstein in How to Be Happier Day by Day