This experiment comes from Science Bob.
Follow the link to see the experiment in action. (You may need to dowload Quicktime to view the videos on the Science Bob website)
Many of you had problems with this experiment. A tip from Adrian Bowden (Science Roadshow presenter) is to use a large jar. Put vinegar in the bottom and sprinkle bicarbonate of soda on top. When the foam dies down, the carbon dioxide gas can then be poured off to extinguish the candle. (Remember to only pour the gas off and not the foam/vinegar).