If you prefer using the keyboard to perform actions rather than the mouse or touchpad, you will like the Key Tips features in Microsoft 2007 products such as Word and Excel.  Unlike other keyboard shortcuts which must be memorized to use (such as Ctrl + C to copy and Ctrl + V to paste), Key Tips do not require memorization.

Simply press and hold the Alt key on your keyboard to display the numerous shorcut options on the ribbon.

Next, press the appropriate key for the desired menu, quick access option or tab while still pressing the Alt key.