Me (in lecture mode): "Well, hon, you know what happens when you assume. You make an 'ass' out of 'u' and 'me.'"
Byrd (rising to the challenge): "Well... know what happens when you make an assumption?"
Me (totally confused): "What?"
Byrd (with a flourish): "You make an 'ass' out of 'u' and 'umption.'"
(Byrd struts off, his logic unassailable.)