There is a feature in MOSS that enables you to gradually shut down the farm for maintenance. This feature is called "Quiescing." I have to admit, this isn’t a word I use everyday, so I looked it up on Dictionary.com and found the following:
"become quiet or quieter"
"To render quiescent, i.e. temporarily inactive or disabled. For example to quiesce a device (such as a digital modem). It is also a system command in MAX TNT software which is used to temporarily disable a modem or DS0 channel."