Sometimes you might feel restricted by the amount of control you have over the brightness and volume on your Mac. When you press the default volume and brightness controls on your Mac, usually F1, F2, and F10-12, there are 16 distinct levels for both brightness and volume. You can, however, fine tune these so that you can have up to 64 different levels.
Try holding down both the Option and the Shift keys along with either F1, F2, F11, or F12. You will notice that the white bar that normally increases by one will actually only increase by a quarter of a square now. This is because you have just unlocked finer control over your Mac's brightness and volume settings!
This has been tested on Mac OS X Lion and has previously worked on other versions of Mac OS X. If I remember correctly, the increments used to be in halves but are now in quarters. I guess Apple has granted us more control over the settings of our system.
If you have any questions or comments, please feel free to leave them in the comments below.