Quickly minimize and restore a Finder window: "Let's say you're working on a Finder window which covers another window (not necessarily another Finder window) on which there is an information you need. What do you usually do? You use Exposé, Command-Tab, etc.
But there's another solution: if you're able to read very fast, you can triple-click (as quickly as possible) the title bar of the Finder window. It will minimize and then immediately unminimize. I don't know whether this is a bug or not, but it only works with Finder.
[robg adds: Somewhat obviously, this also only works if you've enabled Minimize when double clicking a window title bar in the Appearance System Preferences panel.]