Back in 2006 the Campaign for the American Reader blog did a post on the page 69 test.
Marshall McLuhan suggested that you should choose your reading by turning to page 69 of a book and, if you like it, read it.Since then, The Page 69 Test blog has been set up and has been applying the test to novels. The Page 99 Test blog was later set up to deal with nonfiction titles.
The two blogs have recorded the testing of hundreds of books. Take a look around the two sites if your discussion group is looking for titles for future sessions. After the discussion compare your group's opinion of page 69 (or 99) to the tester's opinion.
If your group is having a hard time coming up with a next title to read, bring several suggested titles to the group and have group members each read page 69. Make a decision based upon everyone's opinion of page 69. It could make for some interesting pre-book discussion discussion!
[For more information on the page 69 test, read this article from the U.K.'s newspaper, The Guardian.]