People make a wide range of things with 3D printing and share them on YouMagine. A category that is perhaps a bit unexpected is 3D printed musical instruments. Below are some fun things to be found on the site that you can print.
This 3D printed mouth harp is a modern take on a very ancient musical instrument. Also called a Gogona, Dan Moi or a Kouxian.
Jeff Hertzberg who is a violinist made this violin mute that can also be used for other stringed instruments. His mute design comes complete with an OpenSCAD file so you can adapt it easily for other instruments.
David Perry at OpenFabPDX made the F F F Fiddle an electric playable fiddle.