One of my undergrad chemistry teachers got everyone's attention by bringing in three balloons - one full of hydrogen, one full of oxygen, and one full of equal

One of my undergrad chemistry teachers got everyone's attention by bringing in three balloons - one full of hydrogen, one full of oxygen, and one full of equal parts hydrogen and oxygen. Then (using long sticks) he proceeded to ignite each one with a match. We could all feel the shock wave from the H2-O2 mix going off. Fun at parties? Bad idea most likely.