Existing devices re-purposed for music: Symphony For Dot Matrix Printers.
I've heard it on the radio, it's not bad.

My own instrument from recyclables:
Take an empty pop can and remove the pull-tab. Stab it twice in the side with a small knife-blade and twist the blade so as to open up the holes a bit. Blow across the pull-tab opening while fingering the knife-wounds on the side. I can usually only get three notes out of it, but the creation of the instrument is novel to watch.

Has anybody else tried dandelion stems as drone pipes?