The wife phoned her husband in the office and said, "Darling, come home early, we are going to have my mother for dinner."
"Good." replied the husband, "Make sure she's well done."

My mother-in-law asked me, "If you hate me so much, why is my photo on the mantle piece (shelf above the open fireplace)?"
I told her, "So as to keep the kids away from the fire."

I always know when it's the mother-in-law knocking at the door - the mice throw themselves in the traps.

Last week my wife and I went car shopping, and the salesman asked if I wanted a car with an Airbag. 
I said, "No thanks.  I already have a mother-in-law."