I once did a magic show at school. Can't really remember much, ecept for some string trick and making a key dissapear before the audiences eyes (large elastic band cut and attached to the label inside jacket hidden in the sleeve, and attached to the top of the key (the bit with the hole in it). Cover up that bit with your fingers (just hold it), but with your palm facing you, so the audience can see most of the key but not the elastic bit. Let go and turn your palm to face the audience - it's gone (up your sleeve thanks to the elastic).