Finished the book today. Basically, I did something that I have never ever done in my life, ever. I started and finished the book page to page, start to end, cover t0 cover, prologue, epilogue, acknowledgements, preface, praise for the book, author's bio everything, every printed word in the same day. Non-Stop. Thats how un-put-downnable the book was for me.
It does strike to me that if you liked Freakonomics, the book, then it is likely that you might also like Circles: Fifty round trips through history by James Burke.
Like Levitt, Burke also has a forensic mind when investigating connections between seemingly unrelated events and is an astute student of causality. In fact, Burke has more than one titles that explore such "freak" connections within technology and sociology much the same way as Levitt does in economics and sociology in Freakonomics.
I have read Circles, but it was not as un-put-downnable as Freakonomics, however, the style of the two books was strikingly similar - sort of a journeyistic feeling with an intellectual P.T. Barnum of economics (and, in case of Circles, history).