Dude plays the theme for the animated TV series "The Flintstones" by squeezing air through his hands. You can watch his other works here. This little known art is called Manualism. It is extremely difficult to do and one can take many years of practice to master it. From Wikipedia:
Just as a trumpeter makes sound by blowing air between the lips, a manualist makes sound by squeezing air between two hands.
The hands are held together, trapping a pocket of air between the two palms. Using the fingers of the dominant hand, the air is squeezed out the top, between the base of the thumb and the opposite hand, to form a musical note. The pitch is determined by the force used to hold the hands together. The tighter the grip, the higher the note.
Bass notes may be produced by squeezing the air pocket out the opposite side, near the pinky finger.
Even with years of practice, manualism is very difficult to control. It may be one of the hardest "instruments" in the world to play, and live stage performances are extremely rare.