Top 11 things to say if you get caught sleeping at your desk: 

11. "They told me at the blood bank this might happen."
10. "This is just a 15 minute power-nap like they raved about in the
     last management course you sent me to."
9.  "Whew! Guess I left the top off the liquid paper"
8.  "I wasn't sleeping! I was meditating on the mission statement and
     envisioning a new paradigm!"
7.  "This is one of the seven habits of highly effective people!"
6.  "I was testing the keyboard for drool resistance"
5.  "Someone must've put decaf in the wrong pot."
4.  "Boy, that cold medicine I took last night just won't wear off!"
3.  "Ah, the unique and unpredictable circadian rhythms of the workaholic!"
2.  "I wasn't sleeping. I was trying to pick up my contact lens without
     my hands."

And the #1 best thing to say if you get caught sleeping at your desk:

1.  "Amen"