There was an old man from Nantucket...

limerick (LIM-uhr-ik) noun A humorous, often risque, verse of five lines with the rhyme scheme aabba.
[After Limerick, a borough in Ireland. The origin of the name of the verse is said to be from the refrain "Will you come up to Limerick?" sung after each set of extemporized verses popular at gatherings.]

e.g.,
There was an old man from Nantucket,
Who kept all his dough in a bucket.
His daughter, Nan,
ran off with a man.
And as for the bucket, Nantucket

The following, by Dan Barker, of Madison, Wisc., seems to be a critique of columnist George Hesselberg, of the Wisconsin State Journal:

There once was a parrot named 'Colonel,'
Who read all the papers diurnal.
But his favorite page
On the floor of his cage
Was the Hesselberg page from the Journal."