Add a little WebOS to iOS! Open the app switching on iOS 7, pull an app downwards, let go... weeeeeeee!!
Dismiss apps by pulling them down and letting them shoot off just like a sling shot!
If you're interested the source code to the tweak can be found on GitHub. Otherwise you can download it free from BigBoss Cydia Repository.
If you haven't jailbroken your device you can find instructions at the iClarified Jailbreak Wizard.