R&B isn't the only song source that is used for children's rhymes.
Parodies of Christmas carols and other folk songs are also a rich source for children's rhymes.

For example, here's a version of "WE THREE KINGS":

We three kings of Orient are
Tried to smoke a rubber cigar
It was loaded, it exploded
Now we are seeing stars

We two kings of Orient are
Tried to smoke a rubber cigar
It was loaded, it exploded
Now we are seeing stars

I one king of Orient are
Tried to smoke a rubber cigar
It was loaded, it exploded
Now we are seeing stars
-GUEST,Phil; Date: 24 Dec 00 - 02:24 PM

[I clipped this from a Mudcat thread Christmas Parodies, but now I can't find the URL for that thread].