"Making and Playing Homemade Instruments" by Cathy Fink and Marcy Marxer lives up to its title in that these ladies do indeed show how to make actual, playable musical instruments. Whether you'll want to hear them played on the other hand is a totally different question.
If you view this as a craft video that can make temporary fun for kids, it's fine, but that's as far as it goes. For what it is it's OK, and the hosts are enthusiastic and provide good instruction, I'm just dubious as to how entertained kids will be with this (and this is coming from someone who has loved music since childhood). If you're interested in making homemade instruments with children, this is as good a source as any.