Born to Run by Christopher McDougall

Christopher McDougall's Born to Run is one of the best audiobooks we've heard in awhile. It's a fantastic combination of memoir, anthropology, and science, all focused around the subject of ultra marathon runners--people who run 100 miles or more at a time.  This unusual group includes college party-goers, doctors, and a small group of native Mexicans who live deep in a barely accessible canyon, and the best part of the audiobook is when they all come together to race.

Don't worry if you're not a runner yourself--Born to Run is still fascinating.  You will never forget Caballo Blanco, a mysterious American who lives and runs in Mexico, or Barefoot Ted, who runs barefoot even in insanely harsh terrain.  The story moves quickly, especially when it's describing ultra marathons, and the narrator is fantastic.