What about CDs with those sneaky tracks before track one? Those really creep me out and I can't figure out how to rip them. I believe the Willie Nelson tribute "Twisted Wille" has one, one of the albums by "Mono Puff" has one... and I think TMBG's "Factory Showroom" includes one as well. They only seem to work on audio-only players and you have to rewind from the start to hear them.

Details of how the pre-gap tracks work are here. In an earlier version of that FAQ, Factory Showroom was specifically mentioned, but he seems to have removed that note in favor of a link to http://www.turbine.com/oddcd/ .

There are lots of tricks you can pull with track indexing on audio CDs, some of them have been used as attempts at copy protection, even.

And while we're on the subject, Andy seems to have updated his CDR FAQ with some really interesting information regarding Audio CD copy protection schemes. Great stuff, check it out if you're interested in how CD copy protections work.

Digging up an old thread because I found an interesting piece of text regarding the "city sounds" and voices on the song The Camera Eye. As follows:

The song opens with street sounds taken from the 1978 Superman Movie. The sounds are taken from the scene where Clark Kent arrives at the Daily Planet for his first day of work. The sounds from the movie are edited to some degree but there is no doubth that this is where they came from. The synth intro begins overtop of these background of sounds. The street sounds then change to the sounds of typewriters/teletypers/etc. which is when Clark enters the Daily Planet offices. These sounds fade approximately 50 seconds into the
song.

Incidentally, this text was found at the Rush Tablature Project. I just contributed a transcription change to YYZ there.