Here you can watch a 60 Minutes clip about an orchestra created entirely from landfill materials in Paraguay.
It's very interesting- watch it here
The links below will take you to some suggested sites to get your creative juices flowing.
http://www.nyphilkids.org/lab/main.phtml
http://a2zhomeschooling.com/explore/fine_arts_kids/music/homemade_instruments/
http://www.familycorner.com/crafts-kids-family-2/9-easy-to-make-musical-instruments-for-kids.html
http://www.artistshelpingchildren.org/musicalinstrumentsartscraftstideashandmadekids.html
https://www.mydso.com/dso-kids/activities/make-your-own-instrument
http://a2zhomeschooling.com/explore/fine_arts_kids/music/homemade_instruments/
http://www.familycorner.com/crafts-kids-family-2/9-easy-to-make-musical-instruments-for-kids.html
http://www.artistshelpingchildren.org/musicalinstrumentsartscraftstideashandmadekids.html
https://www.mydso.com/dso-kids/activities/make-your-own-instrument