Quote that sent me into gales of laughter: What is the sound of one hand smacking you upside your head?

Also funny quote that this reminds me of: Remember, when someone annoys you, it takes 42 muscles in your face to frown. But it only takes 4 muscles to extend your arm and smack them upside the head.

I sense a list in the making here. Anyone else have quotes using the phrase 'upside the head' in them? I'll pay in karmic jelly beans (black, of course).