I know that in iOS, several parts of the iDevice's functionality can be accessed from the lock screen. This is useful when you don't want to fumble with a password.
But now I'm starting to wonder: what else can be accessed from the lock screen? I know these:
- Three-home-button tap to invert screen (when Universal Access is enabled)
- Double tap to play music
What else can be accessed from the iOS lock screen?
EDIT:
As Daniel L mentioned,
"It shouldn't produce a bunch of partial answers; a good answer will include a canonical listing (with sources) of what can be accessed from the iOS lock screen. There is a right answer to this question."
Please, make your answer a canonical listing (with sources) of what can be accessed from the iOS lock screen.