Color-less Classic -- A friend at Apple notes that Color Classic users can move the contrast slider bar in the Screen Control Panel all the way to the left, making the screen go pitch black. It would seem that users in that situation are stuck, since they can't see the slider bar any more, but pushing the screen contrast button on the Color Classic's front bezel will bring the screen back up.
Type Faster on an iPhone or iPod touch
When typing on an iPhone or iPod touch, to end a sentence quickly and get ready to start the next one, double tap the Space bar. You'll insert a period followed by a space. You can turn this shortcut on or off via the Shortcut slider in Settings > General > Keyboard.