Just remembered another fun-with-string noise maker. Take a 12" (30cm) boxwood ruler, drill a hole near one end, and attach a piece of string. The string mustn't e too short, but if it's too long you can wind up the excess. Now swing the ruler around your head on the string. (It's probably best do this out of doors.) The ruler will spin on its long axis, making a roaring noise. Stop from time to time to let the string rewind/unwind. If you hit someone with the ruler while it's spinning, you'll almost cetrtainly draw blood, so it's two toys in one. A bit like a boomerang, but without the skill.

Steve