Joe Clark had not much of a chin
"Well, don't worry," said Brian to him
"I can take up the slack
And lead the attack
Cos mine's long as the road to Berlin"

(political limerick...you've got to be Canadian to appreciate it, plus remember the '80's. Joe Clark is still on the scene, somewhat, but Brian Mulroney has departed for greener corporate pastures.)

I agree that the one about the mathematician is exceptional. That last line is a killer.

- LH