Survival Float, a.k.a Dead Man's (Mom's) Float

Instructions from eHow.com on how to survival float.

1. Take a deep breath and hold it
2. Float in a vertical position with your face down in the water. Only the back of your head should breach the surface. The air in your lungs will keep you floating.
3. Relax. The purpose of the survival float is to conserve energy.
4. Let your arms and legs dangle. Your arms may float up to the surface.
5. Raise your head when you need a breath of air. If you need to, bring your arms and legs slightly upward to the surface, then push them downward to help you elevate your head for a breath.
6. Return to a relaxed floating position.

I particularly like the dangling of arms and legs and returning to the relaxed floating position. Conservation of energy. That's what it's all about. That and the breath of air - long, slow, deep breaths of air.