I was looking through Apple's new Calendar widget code, and noticed that you can navigate it with the keyboard:
The Up and Down Arrow keys will jump to the previous or next year, the Left and Right Arrow keys will jump to the previous or next month, and the Home key will jump back to the current date.
Pretty nifty! If only widgets came with Read Me files, so we could know these features exist!
Mac OS X Hints
http://hints.macworld.com/article.php?story=2006012308194211