"Don't Forget This" Hook.
(for wiki.43folders.com's "LifeHacks" section)
Super nerdy, but I stuck a plastic hook over my deadlock so I can hang stuff there. That way I can't possibly forget it when I rush out in the morning (a problem I tend to have a lot). Here you see my rent check ready to go out in the morning.
As Homer would say "I've discovered the awesome power of the hook."