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.
Shorten URLs in TextExpander
If your Twitter client doesn't automatically shorten URLs for you, you can use TextExpander to shrink those long links to tweetable lengths. First, add the Internet Productivity group by choosing File > Add Predefined Group > Internet Productivity Snippets. Then, to shorten a URL using a service like TinyURL, copy the destination URL to the clipboard, and type the abbreviation
/tinyurl to insert the shortened URL at the insertion point.