My girlfriend has a book of limericks, which has been entertaining me recently. A few gems (starting with a metalimerick):

The limerick packs laughs anatomical
into space that is quite economical.
But the good ones I’ve seen
So seldom are clean,
And the clean ones so seldom are comical.

A rocket explorer named Wright
Once travelled much faster than light.
He set off one day
in a relative way
And returned on the previous night.

In a notable family called Stein
There’s Gertrude, there’s Ep, and there’s Ein.
Gert’s poems are bunk,
Ep’s statues are junk,
And no-one can understand Ein.

There was a young lawyer called Rex,
who was sadly deficient in sex;
Arraigned for exposure,
He said with composure:
“De minimis non curat lex”