My cinema display wakes up from sleep in a fraction of the time it took my VGA monitor. Because of this, I'm able to see the desktop before the computer is ready to play.
I looked up at the clock on the menu bar and noticed it was showing the time that I had put the computer to sleep! Before I had time to think, I watched as the clock updated itself to the current time.
I guess this is normal, but I had not seen it before because by the time a CRT lights up, the clock is already updated.