I had a math professor who used to write limericks on his exams to try and relax his students. Here are some of them...

A Mathematician confided,
that a Möbius strip is one-sided.
You get quite a laugh
if you cut it in half
for it stays in one piece when divided!

Pascal, though he had no bad vices,
He did play a lot with his dice(s).
One day he was struck,
That good fortune and luck,
Could succumb to mathematical devices.

Poincare contemplated two spheres,
As the barmaid appeared with his beers,
To reach them he tried,
Only to be denied,
As the distance goes up as one nears.

The author of all three of these limericks is unknown.