The WOD is the workout listed every day (with the exception of rest days) on CrossFit's main page at http://www.crossfit.com/
. For example, today's WOD is max deadlift, max bench.
Regarding your observation about not being able to detect any patterns to the routines, you're absolutely right! Although there is some underlying methodology to the WODs (this was discussed in one of the previous CrossFit journals), one of the cornerstones of CrossFit's approach to fitness is lack of routine or randomness.
I'd highly recommend going to the Get Started section of the website (http://www.crossfit.com/cf-info/start-how.html
) and downloading the free "What is Fitness" CrossFit Journal available on that page. Also, read the rest of the stuff on the Get Started section and if you want more, read through some of the backposts on this board--there's a wealth of information here.
And of course, feel free to ask more questions.