Since the work is not comprised of treadmills and weight machines, there is skill building and (gasp) philosophy behind all this CrossFit stuff. Read some of the hows, whats and whys below.

Form, Consistency and Intensity
General Physical Preparednes
23 Things to Think about when you Squat
Full Range of Motion

For a fantastic library of specific movement standards, check the mainsite library.  For an equally fantastic library of articles, check the mainsite journal.