When you idle your Mac for quite a long time, your Mac will enter half asleep state and shine its beauty. The Screensaver is like this. First time I saw it, I made a big ‘Wow!!’ It is so beautiful, the animation is so natural, that I will skip firework party to watch this screensaver.
You can adjust your Mac screensaver time by using QuickSilver to call the preference pane, i.e.
dsspref. You can choose a lot of screensavers and also you can set the time when the screensaver will be triggered after you idle.
And, Mac also sleep mode. When enter this mode, your Mac will automatically save your energy usage. You can use this when you are doing mountain of works and you cannot predict what time you will drop out in front your desk. You can set this sleep time at Energy Saver Preference Pane with keyword for QuickSilver
Have a nice sleep..