Spiked Coin  – pocket magic trick
One of my favorite pocket tricks is the  Spiked Coin.  I actually bought mine at a local dollar store.  The basic idea is that you place a coin (I threw away the cheap plastic “coin” that comes with it and use a fifty cent piece in its’ place) inside the little chamber. And one by one you drive little swords (likewise, I threw away the plastic swords and use toothpicks or wooden matches), making it appear that the coin has disappeared. Until you rattle the little box, and the audience can hear the coin still in the box.  One by one, the swords (or toothpicks, or wooden matches) are removed, and the little case is opened. And the coin is revealed, as good as new.
It’s more effective with the use of normal materials and works well for comedy or clown magic as well.  For example, if the clown is working with an assistant (or a volunteer from the audience), he can have the assistant put the swords/toothpicks/etc in, one at a time, gloating to the audience how the coin has “magically” vanished. Only to be visibly shocked and upset when the assistant shakes the box to “prove” that it’s gone.  With the toothpicks removed, the clown is proved a fraud, since the coin is still there.