My two cents: I think the first "Timmy Von Tremble" call is the perfect introduction to the Best Show. S&W's usual slow burn might be a bit much for the uninitatied. They might get a little bored at the beginning and only be half paying attention when the set up pays off. I think "TVT," however, will grab their attention right from the beginning. How could you not take notice of the ridiculous set up of two inch tall man? Plus, the silly voice Wurster uses might have them laughing in and of itself. By the time they get to the twist they'll already be immersed in the bit and once Timmy is revealed as a racist the logic and flow of the Best Show will have been subconsciously been indoctrinated in the lister. Also, you don't have to know s-hit about music or whatever to find the concept of a two inch racist funny.
I've played "TVT" to some friends who are not familiar with TBSOWFMU and they pretty much took to it immediately in a way they did not for something like "Gas Station Dogs." Of course, you can make the case they if you don't find "Gas Station Dogs" funny, you're too lame to enjoy The Best Show anyway.
Side note: It's kind of funny how some of the folks I know always mention "This guy is the drummer from Superchunk" when introducing the The Best Show to others as if that's supposed make one pay attention.