I'd recommend *against* the switchboard. (I'm a techie, and it falls into my "don't care for it/bet I could wire that in my basement" category)
I did a twenty-minute show for a room-full of these folk once, and the item that they kept talking about afterwards was a variant of "Murder Most Foul" by Leo Boudreau. And I'm not even a mentalist! -- I did personalize it to the crowd, however, so they found it fun as well as amazing.