If this doesn't offend too many finer sensibilities. or even if it does, something we enjoy doing here at my house is introducing strangers and youngsters to the autoharp and metal knitting needles at the same time. Makes a wonderful rangy dangy percussive sound, and you can parcel out the jobs. Let someone who knows chords play the chord bar and let the kid(s) do the rhythm on the strings with a couple needles.
Kids also learn quickly that if they use a very heavy hand it DAMPS the sound, that a lighter bouncy touch gives em the most for their money.
Blessings,
Barbara