One of the cool new features of Mac OS X Leopard is the search field in the Help menu of each application. Entering a search term in this field will pull up not only help topics related to your search, but anything that appears in the current application's menus (this includes history and bookmarks in Safari).
As you highlight each menu item in the search results (using the arrow keys), that menu item gets pulled down automatically and highlighted with a colored floating pointer. You can then hit enter to activate that menu item. When I first saw it, I wondered if there was a shortcut key for the help menu, so I didn't have to use the mouse (like hitting Command-Space to do a Spotlight search). Well, there is: Command-? (i.e. Command-Shift-/).
This shortcut key is documented in the Mac Help system (under Mac OS X keyboard shortcuts), but it is so awesome, I had to submit it.
[robg adds: You can also customize this shortcut in the Keyboard Shortcuts tab of the Keyboard & Mouse System Preferences panel. Some may dislike the floating blue arrow that highlights the menu items, but the motion really helps my eye find it in the clutter of a complex set of menus.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071027080844612