The Goodnight Kiwi
When I was a kid, staying up long enough to see the Goodnight Kiwi (which signalled the end of broadcasting for the night, Americans) was a sign of true decadence. The sound of this little theme tune is like someone gently massaging a nostalgia lobe. I even feel sleepy when I hear it.
(I also love that there's a tiny amount of completely unexpected NZ-retro stuff on YouTube.)