Unfold, an amazing Cydia tweak, enables you to unlock your jailbroken iPhone by simple folding away the lockscreen. This tweak was completely inspired by a concept made on Dribbble here. The great thing about the jailbreaking community is that once they see a concept which could be possible to implement on an iOS device, they do it. Unfold actually works unbelievably well, no lag whatsoever, it is super smooth.
The tweak is called Unfold, you'll find it in Cydia and it's completely free.