Telekinesis. YEAH, theres an app for that!
Even mild ambient noise muffles the noise of the app.
If you present it right it really freaks people out. I turn my iPhone4 upside down and balance a coin on the bottom edge.
With some intense concentration ;) the coin moves and falls off the edge. I get everyone involved as we ALL concentrate on the coin.
Should be much more expensive.
Love to Golf about iTelekinect