Limericks are five line poems that make use of a complicated sounding strict meter to produce short, often witty or humorous, poems. The form was popularized by Edward Lear in the 19th century, and is considered to only be good if obscene.
Here are some examples I found on this website:
There was an Old Man with a beard,
Who said, 'It is just as I feared!
Two Owls and a Hen,
Four Larks and a Wren,
Have all built their nests in my beard!'
There was an Old Man in a tree,
Who was horribly bored by a Bee;
When they said, 'Does it buzz?'
He replied, 'Yes, it does!'
'It's a regular brute of a Bee!'
There was an Old Man on a hill,
Who seldom, if ever, stood still;
He ran up and down,
In his Grandmother's gown,
Which adorned that Old Man on a hill.
The blog was on Happy Thinking
About a man who had taken up drinking
He's mad and a fool
And a sweaty pustule
Whose sanity surely is sinking.
This Man was a total sad-sack
Whose passwords are easy to crack
Whether true or not
This is not worth a jot
It'd be best if you were all turning back
There was a Young Man with a blog
Who was lost in a terrible Fog
He was asked "Who are you?"
But he had not a clue
And was ever lost in the fog.