Back in grad school I used to do the demonstrations for the freshmen chemistry class. One demo was displaying ballons containing different gases and having the kids vote on which would give the biggest "boom". The balloons oxygen, nitrogen, helium, hydrogen, and a mixture of hydrogen and oxygen. After they'd vote I'd touch a match to the balloon.

Oxygen: pop
Nitrogen: pop
Helium: pop
Hydrogen: POP
Hydrogen + Oxygen: KA-BLAM!!!

The resulting explosion/fireball removed all the hair from my arm and the side of my head. Italso knocked my goggles askew and removed one eyebrow. The campus radio station was in the basement directly below me and the sound of the explosion was broadcasted (not intentionally) throughout the tri-city area.

The next time I did the demo I taped the match to a long stick.

And also used bigger ballonns.

-Blast