There once was a man from Nantucket
Who kept all his cash in a bucket;
But his daughter named Nan
Ran away with a man,
And as for the bucket, Nantucket.


The well known Old Master of Limerick is Edward Lear (1812-1888), and he required the first and fifth lines of the poem to end with the same word. Most modern limericks ignore this rule, but the above one is a great example of how well it can work.