Anatoly Liberman - here's his regular Oxford Etymologist blog - is the author of Word Origins ... and how we know them (Oxford University Press, 2005, ISBN-10: 0195161475) which looks rather fun. Targeted at the lay reader, it discusses etymologies but, crucially, also the processes by which etymologies are discovered (and created): an antidote to the genre of cut-and-dried etymologies of newspaper columns and popular books (and, of course, the Internet - you may have received the ghastly "Life in the 1500s" e-mail).
Perhaps if someone explained to them that, compared to the drama of words, Hamlet is a light farce, they might develop a more informed attitude toward philological research and become students of historical linguistics rather than gullible consumers of journalists' pap.
You can sample Word Origins ... and how we know them at Google Books. At first acquaintance, I like the quirky style and iconoclasm, as in Chapter 5 ("in which people take the cause of word origins in hand, or Folk Etymology") or Chapter 11 ("in which history pretends to raise its veil, or Coinages by Known Individuals").