Ip dip dip
My blue ship
Sails on the water
Like a cup and saucer
Ip dip dip
You are IT!

(Or "not it," or other extensions of that last line...)

Used in the playground, usually by the Alpha Boy, when picking a team. He points to a different kid on every syllable. He could nefariously alter that last line if he could foresee that "it" would be an undesirable member of his team! Alternate "captains" would use the rhyme repeatedly until everyone had been picked. Naturally, if you were like me, i.e., the three-legged carthorse of football, you would, humiliatingly, be the last one picked...

From Radcliffe, Lancashire, in the 1950s.