iBounceMeter is a simple application which exploits the accelerometer of the iPhone.
The display shows the G forces experienced by the iPhone.
The user interface is very simple, there are no interactions with the application apart from the movement of the iPhone itself.
Initially the display runs for a second and then stops.
The display is reactivated when the iPhone experiences a G force greater than 3/4 G and continues for five seconds after the G force drops below this level.