Here's what I love about this book test.
1) You can genuinely use pretty much any book they
give you. Walk into any bookstore, library or living room and let them give you a book. So the book
is fully examinable. You could even do it with foreign language books if you wanted to.
2)
They can genuinely choose any page they want.
3) You can predict what word they will pick
in any way you'd like (e.g. have it written on the ball of paper tossed around by the audience to
choose them).
4) They'll never be able to accuse you of peaking at the word. They take the
book away the second it's closed.
5) If you want to, you can have it be that they pick one
word and then either change their mind or a second spectator picks a totally different word from the
same book.
This thing is sheer genius.