Tour Divide - 'Rope a Dope' the Sleep Monster

How do you fight the "sleep monster" on an 18+ hour riding day?  Take a nap.  15-20 minute naps were my key to success.  I always felt better in the hours after a power nap than I did when I fought it.  Don't sleep to long though or you may feel worse or sleep through.  On my best days (140-150 miles)the power nap helped me defeat the monster.  On my short 90ish mile days the sleep monster won.