Who's on First definitely has to be the best. I'v got a copy on my empeg as well, 64 bit. Had it for 3 years, don't quite remember where I got it from though. Here is a link to a lot of A&C routines, I just found it so I can't yet verify the quality, but I'll check tomorrow.

First time I remember hearing about it was in the movie Rainman with Tom Cruz and Dustan Hoffman, although I don't believe they actually have the whole skit in there.

For those of you who haven't heard it the full script is here, but it still is much funnier to hear them do it.

Enjoy,
Daniel