Sent to you by Chris Hunter via Google Reader:
Android's lock screen supports a variety of different unlock methods as well as widgets, which allow you to take action and view information from the lock screen. To really master your device, you'll want to tweak your lock screen.
Lock-screen widgets can help you interact with your phone without unlocking it. They were added in Android 4.2, but older versions of Android can use third-party lock-screen widgets. If you don't like them, you can disable them.