Emenius Sleepus

Here's a crazy little piece of information for you.  The average human circadian rhythm isn't actually 24 hours, its 25 hours (variable and with rounding).  That means that naturally your body wants to go to bed an hour later then the night before and hence wake up an hour later as well.  If it wasn't for light our bodies would continue this pattern all the way to resetting itself 24 days later.