One of the oldest musical instruments in the World, the amazing didgeridoo, made by the aboriginal people in Australia thousands of years ago.
It is a wind instrument played by vibrating the lips to make sound. If you can find an old steel or pvc pipe lying around, you are in luck. Even the pole of your shed that some termites ate can be used to make a nice didgeridoo. The best length is between 4 to 6 feet long, and around two inches in diameter.