A clerihew is a four-line humorous verse about a well-known person. They’re named for Edmund Clerihew Bentley, who invented them, and they get pretty erudite, for some reason:

Sir Karl Popper
Perpetrated a whopper
When he boasted to the world that he and he alone
Had toppled Rudolf Carnap from his Vienna Circle throne.
(by Armand T. Ringer)

Sir Christopher Wren
Said, “I am going to dine with some men.
If anyone calls,
Say I am designing St Paul’s.”

Alfred, Lord Tennyson
Lived upon venison;
Not cheap, I fear,
Because venison’s dear.
(credited to Louis Untermeyer)

George the Third
Ought never to have occurred.
One can only wonder
At so grotesque a blunder.

The world’s densest clerihew was composed, over breakfast, by W.H. Auden and Chester Kallman, in honor of New Yorker poetry editor Howard Moss. It manages to rhyme the names of three people in four lines:

To the Poetry Editor of the New Yorker

Is Robert Lowell
Better than Noël
Coward,
Howard?