This is the kind of poem I used to get in trouble for. For English class, I'd write a normal poem and get good marks, then I'd hand in something like this to mess with the teacher.

Green Things

What do you find at the back of the fridge?
Green things.
What grows on the feet of your cousin Midge?
Green things.

What tickles your nose when you have to sneeze?
What do doctors insert when they work on your knees?
Green things.

What do frogs mate with when they are in heat?
Green things.
What do you find when you turn down the sheet?
Green things.

What goes into your dog and out of your cat?
What grows under logs and smelly door mats?
Green things.