One which I remember (imperfectly) from my schooldays is:

My son, Augustus, off to school one day
Was feeling quite particularly merry
When someone asked him: "What's the quickest way
To get to [Highgate] Cemetery?"
"The quickest way!" replied my little Gus
And shoved the fellow underneath a bus.

Does anyone have a correct (!) version or an author for this?

The other important question to ask, of course, is why has this piece of doggerel stayed with me for nearly 50 years?