Few skills are as useful for a Friday afternoon as the rewarding power nap. The Ririan Project introduces 10 benefits to power napping and details four styles of power nap: nano nap (10 to 20 seconds), micro nap (two to five minutes), mini nap (five to 20 minutes), lazy man's nap (50 to 90 minutes) and the traditional power nap (exactly 20 minutes). Contrary to popular opinion, napping isn't for the lazy or depressed. Famous nappers have included Bill Clinton, Lance Armstrong, Leonardo da...