My primary Linux box is a home-built machine based on a Gigabyte GA-MA78GM-S2H motherboard. I have it down in the basement. The keyboard, video, and mouse on my desk are connected to it via a Belkin KVM Extender.
Now don't get me wrong - this setup is great. Whatever sounds the box makes (fans, etc), I don't hear it. I can also turn the computer off. But the fact is, in order to turn the computer on, I have to physically and in person go down into the basement and press the button.
The solution is called "Wake-On-LAN" and here's how to set it up on the GA-MA78GM-S2H.
Go into BIOS setup and under "Power Management Setup" there's a menu option called "PME Event Wake Up". Enable it. PME stands for Power Management Event. If you look up Power Management Event in Wikipedia, you will find no mention of Wake-On-LAN. Yet, enabling this option does activate the board's Wake-On-LAN functionality. Why isn't the menu option entitled "Wake-On-LAN"? I have no idea.
Since I'm going to be sending the magic packet from a Windows laptop, I next downloaded and installed Anil Rhemtulla's "WOL - Magic Packet Sender" from here:
After entering the required information
I hit Send and Voila, the machine powered itself up. No more trips to the basement!
One day later
I've tested it a bunch of times and I still can't believe it works! That said, after awhile the computer seems to get confused and hangs up after POST, in the AHCI initialization phase, necessitating a cold power cycle. Another caveat: after the cold power cycle, the computer doesn't react to the magic packet because the motherboard isn't in standby mode until the power button is pressed.