The background one needs for this joke is:
1) Mrs. G's first name is Susan; and
2) The Gruntleds still haven't forgiven Neville Chamberlain for selling out Czechoslovakia.
I sent this message to our eldest daughter:
"I am going to take Mom to the Czech Republic. They have the best Sue datin' land."
I cc'ed Mrs. G., and waited for her to open email. I knew she had opened this message when a belly laugh emanated from her corner of the bedroom.
She forwarded the message to her relatives.
Daughter #1 replied: "Feel the inter-state GROAN. Don't just hear it, FEEL it."
My father-in-law replied: "Very possibly the worst pun I have ever heard or read (or smelled)."