from didgequest.com
"The didgeridoo, also called a Yidaki, is a primitive instrument dating back 40 thousand years. It is created and played by the aborigines of northern Australia. The didgeridoo is typically made from the stringy bark or woolleybutt eucalyptus sapling, and hollowed naturally by termites or white ants.

The history of primitive instruments such as the didgeridoo is based on the tribal need for 'medicine man' or shaman. The healer of any clan or community uses different instruments as a tool to help take members of the community away from the ordinary occurrences of everyday life. The 'other world' or eerie sounds of their instruments were used in ceremonies and rites of passage. Didgeridoos, drums, conch shells, bull-roarers, bells and most musical instruments create the space for people to drop out of their normal patterns of life and indulge their spirits to wander.

How is its unique sound created? Technically, the soft fluttering of a person's lip plays the didgeridoo accompanied by two other levels of self generated sound. Much like the trumpet, your air-stream passes through your vibrating lips to create truly unique, sometimes mystical sounds. I hope you find as much calmness and vision as I do when you play, and that you will peacefully play with the rhythm and tone of the planet."

A 2005 study in the British Medical Journal found that learning and practicing the didgeridoo helped reduce snoring and sleep apnea by strengthening muscles in the upper airway, thus reducing their tendency to collapse during sleep.This strengthening occurs after the player has mastered the circular breathing technique.