Last Shabbos, my young daughter found a grogger inside the shul and played with it away from adults and at an appropriate time. A four-year old Orthodox boy told us that it was muktzah and that she should not play with it on Shabbos. It was a purely mechanical noisemaker, the kind that you spin around.
I normally defer to these kids because they usually know more about Jewish laws and customs than I do, and so I agreed to take it away from her. Afterwards I had doubts about whether he was really right. What is it about that grogger that would make it muktzah? The only thing I can think of is making noise on Shabbos, but these kids often make tons of noise anyways. His father does reprimand him and his sister pretty regularly about such-and-such being muktzah and not appropriate for Shabbos, so I am assuming that he has been told the grogger falls in this category.