Being a professional lyricist I love good limericks for their form, shrewdness and conciseness. One of my favorites goes like this:
On the chest of a barmaid at Yale
were tattooed the prices of ale,
and on her behind,
for the sake of the blind,
was the same information in Braille.
Unavoidably the best limericks are a bit naughty or even vulgar. I guess it is because it's more fun to be a little dirty with style.