I think everyone who doesn't get into the Best Show by their own curiosity should have to be a dummy for a call or two.
I remember, before I got wise to Wurster, someone showed me the "Kid eBay" bit from Hippy Justice. To this day I still think it sounds less like a bit and more like something remarkable happening on the radio. I imagine it was not unlike how early adopters felt when "Rock, Rot, and Rule" first aired and then made the rounds. If you ask me, just tell people to listen to something like "Kid eBay," "Rock, Rot, and Rule," the first Zachary Brimstead call, the Springsteen book, or even the Bruce Willis prank phone call. Don't say anything about it beforehand. Let them believe in the scene. These are ultimately more accessible than something where Wurster is putting on an affectation like Philly Boy Roy, or the silly Big Bill/Little Bill, or the underrated and absurd call about Mike Jackal and his band PUNK, which are all great bits for someone who already knows what Scharpling & Wurster is to start with.
And then, like buffcoat says, they'll eaaaaaaaaaarn it!