Here's one for the book.

When my mom was talking about HER children, and my dad was trying to reason with her (never a good idea), he was explaining that we were his children too. (sidenote - my mom allways instilled in us the values of marriage and fidelity)

My mom paused - tried to make sense of what he said, and came up with the only reasonable explanation.

"well then, I must have had a lot of affairs."