Graviboard is a cool new Cydia tweak developed by Conradev. Once activated, it will make the your homescreen icons loose gravity. There are a few different settings of gravity to choose from such as Earth, Moon, and Zero Gravity.
The effect actually works really well and the icons even gravitate towards the direction you tilt your device to. Very funny prank to play on someone, where instead of allowing them to select an app, it will only allow them to fling it around. Graviboard works on all iOS devices running iOS 4.x.
You will, of course, need to have a jailbroken iPhone or iPod touch to install it. Follow our step by step guide posted here to jailbreak your iPhone, iPad or iPod touch with Redsn0w on iOS 4.2.1, or with Limera1n on iOS 4.1 if you haven’t already.
Graviboard is available now from Cydia under the BigBoss repository for $2.99.