Variations:
Kids use almost any words they can think of...
Double double ice ice,
Double double cream cream.
Double ice, double cream,
Double double ice cream.

Instructions:

Face each other. Hold your hands up
As you're saying the rhyme, turn your hands back and forth.
Whenever you say "double," both hands are facing towards you.
Whenever you say "this," and "that," your palms are facing away from you.

Do it fast - it's not as easy to do as it sounds! :)