Yes, today (12 May) is National Limerick Day, which falls on the birthday of English artist and poet Edward Lear (born 12 May 1812), who popularized the five-line humorous poetic form in his Book of Nonsense, first published in 1846. (More details here, via The Smithsonian.)

In addition, as blogger and writer Richard Bist explains (see here), not all limericks are naughty. Below, for example, is a little limerick I wrote about Adam Smith’s “invisible hand”:

Markets may appear quite unplanned,
But by a hidden force both subtle and grand,
Though each man seeks his gain,
It’s clear to explain:
They’re all led by an Invisible Hand.

And here is another one about the famous “Adam Smith Problem”, i.e. the apparent or real disconnect between Smith’s Theory of Moral Sentiments and his Wealth of Nations:

Adam Smith, two tomes did he write,
But the books made many scholars fight,
For one spoke of self-gain,
The other, of empathy’s reign,
Leaving critics to wonder who’s right!