I'm not really sure what you're looking for, but this is a favorite:
http://www.sendspace.com/file/qa9m7f
It's one of the Zeph calls (the third, I think - it's from the 9/26/06 show) - it's the one where Zeph admits to his porn addiction, talks about his preferred proportions of vodka and cola, and names his favorite superheroes. It's a little longer than you'd specified (about 6:20), though I suppose it could be edited.
Seconded Thirded. I think Zeph, top to bottom, is the most hiliarious and brilliant (if underutilized - but maybe that's the point) character ever on the show, and that's saying something. And (I think) he was totally made up on the spur of the moment, too, AND I think he was just adapted on the fly to be Rose Marshack's uncle. Genius!
That's the pause that really refreshes.
ZEPH: Guess what else he sprays Pam on.
TOM: What?
ZEPH: ... ... ... Guess.