Give me a real-life, non-trivial use of the State Pattern

One real-life use of State Pattern I have seen so far is in a Video Player capable of playing online video.

You have to handle playing, paused, buffering, connecting, seeking and even other states.

When the player is in playing or paused states, it is responsive to user interaction events.
When the player is in "connecting" state, it might not have enough data to know the video duration and so the seek bar should be disabled.
Once the player is connected, it will move to buffering state. In buffering state, the user can seek, or stop the video. But if he tries to pause or play the video, the command is saved for later, so that when the buffering is done, the video is either paused or start playing. etc.