The first one was my response to someone asking me to QUICKLY make up a limerick. As I recall, he was not pleased with this result, but it got him off my case:
There was a young man from Chicago
Who said, “Nothing rhymes with ‘Chicago.’
Since I don’t have the time
To make up a rhyme,
I guess I will just say ‘Chicago.’”
I don’t remember where I got this one from, but it has been firmly lodged in my brain for a long time:
He lived by the sewer,
By the sewer he died.
The police called it murder,
But it was sewer-side.