This is a rather long joke but it fits the bill in this thread

There was an improptu poetry competition in outback Australia.
Many would be poets turned up at the Black Stump Pub.

The rules were that a key word was given and it had to be in a certain place You had 5 minutes to make up a 4 line poem. The judges had a hard job

After a long day the two finalists were a shearer and a minister.

They tossed a coin and the minister was first. The shearer was taken to a nearby house out of earshot.

The keyword was Timbuctoo and it had to be the last word. after 5 minutes the Minister came up with

Been around for many a year
visited places far and near
souls I've saved are quite a few
including some in Timbuctoo

loud applause and the shearer was sent for.

after getting his instructions the Shearer told his poem

(for those unaccustomed to Australian slang a shiela is a woman)

Tim and I a camping went
met some shielas in a tent
they were three and we were two
so I buck one and Timbuctoo