Research is starting to show what most of us have known all along: naps are wicked good for you. However, there's a difference between a "good nap" and a "power nap." Mens Journal has written up a practical guide on how to achieve the mystical power nap:The first consideration is psychological: Recognize that you're not being lazy; napping will make you more productive and more alert after you wake up.Try to nap in the morning or just after lunch; human circadian rhythms make late afternoons a more likely time to fall into deep (slow-wave) sleep, which will leave you groggy.