I remember these from my misspent youth:

The gum-chewing girl and the cud-chewing cow
Seem somewhat alike, but different, somehow.
Ah, yes! There it is! I see it all now!
It's the intelligent look on the face of the cow!

OR

Moses supposes his toeses are roses
But Moses supposes erroneously.
For Moses, he knowses his toeses aren't roses,
As Moses supposes his toeses to be!

OR

The breezes, the breezes,
They blow through the treeses.
They blow the girls' skirtses
Above the girls' kneeses.
The college man seeses
And does what he pleases
And spreads the diseases
Oh Jeezes! Oh Jeezes!

Dave Oesterreich