One of the things i like most about (gnu/?) linux, other than everything, is how you can get it to do things you never knew you wanted... and that's what i'm all about, i like to dig down the stuff that creates the WOW-effect, even if it has little or no purpose at all. Being able to convert 8 friends so far, makes me certain that these things really do work on a psychological level.
so this small tutorial can be categorised under CUSYCDWLASBATBAITYFOMGTWALA (Cool Useless Stuff You Can Do With Linux, And Still Be Able To Brag About It To Your Friends, OMG, That Was A Long Acronym)
OK, let's start..
I don't know if you can do this under most linux distributions (obviously i haven't tried), but i can bet you it's easiest with Yast , the incredible system manager that comes packaged with open/SUSE Linux. so if you are using another distro, you might want to check it out, and tell me how it went. (don't bother if you are using Ubuntu, i'll just make fun of you)
Step1: Start by opening Yast as root user, or if you are a command-line junkie like myself, type su then yast2 (or yast if you are allergic to X graphical interface)
Step2: Select "System" from the left pane, then "/etc/sysconfig/ Editor" from the right
Step3: A new window will open showing a tree-view menu, expand it as follows: Other > etc > sysconfig > shutdown > HALT_SOUND
Step4: Change the Setting of: HALT_SOUND to "octave" from the drop-down menu (Tab your way to it then press down button if you are using CLI)
Step5: Save your settings, then shutdown/restart your machine, and listen to it sing =)
Step6: Show it off to your Windows friends, then tell them to go fuck themselves