Why Won't They Just Sleep In!

My children hate sleep.  At least that is my assumption based on the fact that no matter what time they go to bed, they love to come wake me up any time between 5:45am and 6:30am.  I just do not understand it.  This past Friday night we had a couple families over.  While parents enjoyed a bottle (or possibly a lot more than that) of wine and dinner, the kids were able to run around until their hearts content.  This led to children falling asleep in front of a movie at 10:30pm.  One would assume that this would be late for all children and due to complete exhaustion, they would sleep in.  Apparently not my boys.  While I am texting with a friend at 9am the next day about what a good time we had with them, she mentioned that her child is still asleep.  WHAT?!  All three of mine have been up since 6:30am!  NOT FAIR.  When will they learn that sleep is Ah-mazing?  Oh, I hope soon.