One of my students told me that she and her husband were singers in a local chorus. They were practicing one night and their 3 yr old misunderstood the words. Instead of singing ....and unto us a child is born, he sang...and unto us a Chinese bone.
Of course there's always Good King Windowsnot looked out over the feets of Sweden.
Then there's the ever popular While Shephards washed their socks at night...
What are some of yours?