Ha ha... On the note of university administrators:
The Dean, speaking to the chair of the Physics Department:
"Why do I always have to give you guys so much money for laboratories and expensive equipment and stuff?
Why couldn't you be like the math department? All they need is money for pencils, paper and waste-paper baskets!
Or even better, like the philosophy department. All they need are pencils and paper!"
(Found this one when I was looking for that mathematician in the hotel room joke)
That's another classic one.
There's a very dirty one that ends with "...he said to the prostitute, `I can't tell the difference, I'm a topologist.'"
But that is just too hot for FR.