What time is it? Not “approximately” but down to the nano-second. Check out the Atomic Clock Sync utility from WorldTimeServer.com. Now in Version 3.0, Atomic Clock Sync automatically synchronizes your computer’s clock to National Institute of Standards and Technology.
I also use a utility called “L-Clock” which puts a configurable clock on my System Tray. Now I will always know what time it is, despite my wife’s insistence that time has no meaning for me!
There are, of course, many reasons to have an accurate clock. If you use an online backup program, for example, you will want to schedule your backups for 3AM when you are most likely not online. An accurate system clock insures that your scheduling does not cause a utility to run when you need full processing power.
Atomic Clock Sync can be run manually, or set for automatic updates. Highly recommended.