Limericks are to poetry what slapstick is to theatre. They're completely irreverent, sometimes crude, and a lot of fun.
The origin of limericks is unknown. Some believe they were created in the 18th century by Irish soldiers returning to Limerick, Ireland, from France. Whatever its beginnings, the poetic form wasn't called a limerick until long after the verse had been in use.
Limericks were known as nonsense verse. Improvised by peasants and in pubs, nonsense verse developed a reputation for low-brow humor.
A limerick ain't like a sonnet,
No lace, no frills, no bonnet,
It can be absurd
And quite silly I've heard
But, hey, it's fun, dog-gone-it.
Nonsense verse became popular in 1861 when English poet and illustrator Edward Lear reprinted his whimsical limerick collection "A Book of Nonsense" under his own name. (In the first edition he used the pseudonym Derry Down Derry.)