Here's one that I use pretty regularly...
SwipeAway is a jailbreak tweak that simply allows you to close all the apps that are running on your iOS device by a single swipe in the task switcher. Just open up the task switcher, and the swipe up or swipe down (select in the settings) to close all the running apps.
That’s it, just swipe and all the apps are closed. There is only one setting, in which you can select between swiping up and swiping down to close all your apps.
I give this one two Freakies: