The following video shows a simple combustion experiment, the development of a candle flame in microgravity, aboard the Russian Mir space station.

[youtube=http://www.youtube.com/watch?v=IgzCMKdAYuI&w=700]

The following video from NASA Glenn Research Center explains the phenomenon seen in this experiment and the difference between candle flames in one gravity and microgravity.

[youtube=http://www.youtube.com/watch?v=J4lQvuH8ATc&w=700]