An article in the current "Children's Folklore Review" has some good ones. Here are a couple.

Australia, girls in playground flipping up their skirts and chanting;

Flintstones, Flintstones, yabba, yabba, doo!
Fred does the bow,
Wilma does the curtsy,
Pebbles shows her knickers,
And we all go "Wow!"


Mary had a little lamb,
Her father shot it dead.
Now Mary takes her lamb to school
Between two hunks of bread.

The night was dark
The sky was blue
Down the alley
A shit wagon flew
A bump was hit
A scream was heard
A man was killed by a flying turd.

"Children's Oral Poetry: Identity and Obscenity," C. W. Sullivan III, p. 67-77; Children's Folklore Review, vol. 31, 2008-2009.
Children's Folklore Section of the American Folklore Society.