Four & Twenty Dinosaurs

One of my very favorite poetry fun takes some advanced planning but so much fun with most age groups. Get a copy of Four and Twenty Dinosaurs by Bernard Most - still available as a paperback.

Make a list of the nursery rhymes that are parodied in the book.
Then put the book on your own shelf for a bit, and find standard editions of the nursery rhymes that Most used in his book.
For the younger kids you will want to repeat the poems so they are well familiar with them - and can recite them with you. So reread, reread etc. over a period of a few days/weeks. Practice encouraging the listeners to chime in on the recitation of the poems.

Sing a song of sixpence,
A pocket full of rye;
Four and twenty blackbirds
Baked in a pie.
When the pie was opened,
They all began to sing.
Now, wasn’t that a dainty dish
To set before the King?
The King was in his countinghouse,
Counting out his money;
The Queen was in the parlor
Eating bread and honey.
The maid was in the garden,
Hanging out the clothes.
Along there came a big black bird
And snipped off her nose!
With older kids most likely (hopefully) they will be familiar with the poems you will will just need to activate their schema regarding the poems.
Then one day pull out Four and Twenty Dinosaurs and without introduction read aloud the poems encouraging them to chime in on the familiar rhymes -- pause only when the twist is coming.