How tired am I?

Sometimes, when I'm tired at work, I play a game of Solitaire.  It's a little test of how alert I am.  I mean, if I'm so tired I miss the fact that the red eight sitting there ought to be on the black nine, there's something wrong.  I'll usually spot it eventually, and then I'll be, "Dude, how long was that red eight sitting there?  I'm pretty out of it."

So, I started playing solitaire a few minutes ago.  And the VERY FIRST move I made was to move that black ace over onto the red two.

Had to be at least ten moves later when I thought, "Wait a minute."

I need a serious nap.