There's a story about Brendan Behan being asked to give a talk at Oxford. He is alleged to have had a few drinks before hand and when he addressed the audience he was asked the difference between Prose and Poetry he said "Poetry rhymes and prose doesn't".

He was asked for an example and I don't have the exact verse but it was something like :

I love to go to Dollymount,
I love the Fun and Frolics,
I like to go in paddling
And get wet up to my kneecaps

"Now that was prose, If I had gone in another few inches it would have been poetry".