Carbon dioxide (CO2) is cool stuff. One of the cool things about it is that it's both inflammable. It's also heavier than air. Because it has these properties, you can actually fill a jar with it and "pour" it onto a flame- and it will go out in an instant. This tutorial will show you how to do it yourself.
This tutorial is fairly simple and doesn't require much besides some time and these tools:
1. A glass jar
2. A source of flame (lighter or matches)
3. A candle
4. And a balloon of carbon dioxide (not pictured). If you don't have any on hand, learn how to make it.