Along the lines of this trivia answer I provide this video clip that I just came across.Exhaust Port said:I figure I'll answer my own question so it doesn't go unanswered.
The opening melody for the instrumental is actually the morris code for the letters Y-Y-Z. YYZ is the 3 letter identifier for the Toronto Airport which is the home town for the band. More specifically the local navigation beacon also has the identifier YYZ. Pilots routinely monitor the navigation beacon frequency to listen to the co-transmitted morris code identifier to make sure they are navigating off the correct frequency.
The drummer, Neil Peart, was taking flying lessons and apparently decided that the YYZ morris code had a good rhythm to it and worked it into an instrumental musical piece. Hence the name of the song as well as the opening rhythm.
http://www.bobbysbrane.com/animation fun/animations/YYZ video-Rush.wmv
Simply amazing! Warning, it's about 43MB but well worth the download time.