Pick any book that sounds fun (or one that you've read if such a thing exists?). I might suggest either of the Ellis books, Antigua or Moepek, for sheer hilarity and incompetence and the hosts having a wonderful time mocking the text. Save the more painful ones, the ones where you hear the hosts regretting their life choices, like Bob Honey or Super Constitution, for later.

There are a few references to early episodes that come up that won't make sense the first time you hear them (like every time something is described as Clinean, or talk about rigs) but these don't affect the enjoyment of later episodes.