Forget Flashing Custom ROMs: Use the Xposed Framework to Tweak Your Android
Many low-level tweaks can normally only be performed on Android by flashing custom ROMs. The Xposed Framework allows you to modify your ROM without installing a new custom ROM. All it requires is root access.
Sure, you may want to flash a custom ROM like CyanogenMod to get the latest version of Android or use a wide variety of tweaks, but the Xposed Framework makes it possible to perform small tweaks without replacing your Android operating system.