Place a paper napkin over your cupped hand. Push the center of the napkin into your cupped hand with the index finger of your free hand. As you do this you will secretly poke a hole in the napkin. Grab an olive or other small object and place it in the space you made with your finger but don't let it fall through the hole yet. Now pretend you need a magic wand and grab a straw or stirrer with your free hand. While attention is on the hand grabbing the wand you can drop the olive behind the bar or if you're sitting at a table you can drop it into your lap. Now pass the "wand" over the napkin, say some magic words, and tear the napkin apart showing that you've made the olive disappear.