I'm a huge fan of spoonerisms, named after William Archibald Spooner. Apparently, there are very few substantiated slips of the tongue, but he is accredited with saying lots of things, like:
"It is now kisstomary to cuss the bride."
"The Lord is a shoving leopard."
This weekend, I went with some friends to a Scott Hahn lecture, and he shared a fantastic spoonerism by an abbot. Apparently, this abbot was the main celebrant at a Mass in a basilica. We're talking packed house and bishops and cardinals con-celebrating.
At the end of Mass, he said, "This ass is mended, let us go in peace."
So much truth in the slip of a tongue sometimes.