Here's an American jump-rope rhyme which I jumped to as a kid. It's irregular, which qualifies it for unusual, I suppose.

How to spell (drag "spell" out for two beats) Mississippi. Capital M, I, crooked letter, crooked letter I, crooked letter, crooked letter I, humpback, humpback, I!

On "crooked letter" which is s, you cross your legs. On "humpback", which is p, you hunch over, all while jumping.