Flaming dragons: Take a mixture of approx. 90% diluted washing up liquid and 10% glycerin and bubble methane gas through it. Pick up the bubbles in WET (v. important!) hands and set fire to them - very exciting! (Goes without saying, but sleeves rolled up, hair tied back, etc.) Spontaneous combustion: Get a piece of paper and crumple it into rough cup shape. Put it in a fume cupboard and pour some KMnO4 powder into the cup. Add a squirt of glycerol. Now QUICKLY scrumple the paper into a ball and move back. It will catch on fire in a few seconds and burn with a brilliant purple flame.

Reactivity series- Play your cards right, kids turn over a picture of a metal, then shout higher or lower for the next one.(works well for pH as well) A nice reaction to show displacement of metals, also very useful in extracting metals: Mix equal portions of Copper Oxide and Zinc powder. Pour on to an old heat proof mat (my heat proof mat didn't look happy after this). Using a bunsen, blast one end of the line of powder untime it 'ignites'.