I've been working on a system that requires exceptionally high uptime. As such, making major releases takes a couple weeks of testing and preparation. I usually end up doing these releases at 2 am; they are fully automated and things almost always go off without a hitch.
It is somewhat anticlimactic though - there is a 30 second service interruption while perlbal and mod_perl shut down, the postgresql database is upgraded in place, and then perlbal and mod_perl start up again. So all of my work is done upfront; reminds me of the scene from the movie "Lost in Space" where the Jupiter One is ready to launch, and the pilot says "And the monkey pushes the button."
Linus Torvalds recently blogged about the kernel release process, which is kind of like what you described also. (The frenzy starts after the release, when all the patches that were kept in orbit by feature freeze start raining down.)
