In this podcast, Musicruz gives us an in-depth discussion and demonstration of Activator, a jailbreak tweak which allows for gesture-based controls of almost anything.
If your iDevice is jailbroken, it's likely that you already have Activator installed, even if you don’t realize it. Many other jailbreak tweaks rely on Activator to work, so they install it automatically as a dependency. However, Activator does a lot more than just work with other tweaks, and you can use it to make your life a lot easier. Things you would normally have to do manually on your iDevice can be done with simple gestures using Activator.
Activator is available from Cydia on a jailbroken device.