Cyanogen gestures means your screen doesn't need to be on for your phone to be useful.
There are a handful of amazingly clever ideas out there for accessing certain parts of your phone as quickly as possible. Motorola's double screwdriver twist to launch the camera, Samsung's double home button tap, and LG's double volume button tap are among the best. Each of these behaviors are designed to get you access to the camera as quickly as possible, so you can go from pulling the phone out of your pocket to taking a photo as quickly as possible.
Unfortunately most companies stop at launching the camera, but there are plenty of other things users would like to be able to access with a single motion or gesture. Those with Cyanogen OS devices, or folks running CyanogenMod on supported devices, have a few more options at their disposal thanks to the gesture system on this version of Android. Here's how they work.
Gesture control allows you to trace a series of gestures on the display while the screen is off and have the phone respond. You can trace a "V" to activate and deactivate the flash on the back of the phone when you need a quick flashlight, trace a left or right arrow when you want to skip tracks on your music player, and draw a circle on the display to activate the camera. These gestures are complicated enough that you're unlikely to accidentally trigger them in your pocket, but fast enough to launch your action much faster than waking the phone and navigating to the same function.
Activating these features on your phone is simple. Head to the Gesture section in Settings, and flip the toggles for the gestures you want to use. Once that toggle is set, you can turn off the display and trace away. Having the feature enabled doesn't consume any noticeable amount of battery, unless you accidentally activate the flashlight in your pocket and leave it on for a while. Fortunately that's not likely to happen, and the feature can be disabled just as quickly if it doesn't suit your needs. Enjoy!