A Twitter denizen inquired how to be able to tab between two or three button in a dialog instead of having to use the mouse to click the one in particular.
Go to System Preferences > Keyboard > Shortcuts. At the bottom you will see a setting for "Full Keyboard Access". Click the button next to "All controls". Afterwards, you'll notice that selected buttons will have a focus ring. You'll probably notice some other UI elements will have focus rings, too. Which is why I only toggle it on (Control-F7) for testing. It's a bit too distracting for regular use at my house.
I mention this as a tip because many of my scripts use two or three buttons and if you are mouse-averse and keyboard-loving then it should be a treat.