Well, after asking a track coach, and trolling the CrossFit forums, as well as doing a lot of reading and some basic do-it-myself therapy, I've self-diagnosed...myself...with patellar tendonitis. I actually feel pretty good about this diagnosis because A) it fits with both knees being terribly sore, and B) they seem to respond very well to the treatment (icing, stretching, resting, etc.)
At first I was afraid that lots of years of soccer and ultimate frisbee had finally caught up with me, and that tons of slight injuries had finally started to accumulate against me. But the one weird issue was that it was evenly painful in both knees, which a sprain/turn/etc should have targetted more on one side or something. Also, since the pain is right up front, in the "middle" of the knee right below the patella, it's unlikely to be a meninges kind of thing.
It was the track coach (Hi, Lee!), who pointed out that it might be patellar tendonitis, or Jumper's Knee, as its more commonly known. So I did some reading:
The short version is this: There is a tendon that connects the patella to the shin. When you do exercises that create a lot of impact on that tendon (box jumps, double-unders, running, etc), *especially* if you are not yet in perfect form on those exercises (*double-unders*...daily!!!), then you are banging the crap out of those tendons. Also, since the way I exercise targets both knees very evenly (unlike say a basketball player who might land on one leg more than the other, depending on her technique), that also explains why both knees are equally sore.
Everything said pretty much the same thing. Short-term therapy is to stop pissing that tendon off (ie, rest it), ice it, and make damn sure to stretch all the muscles around it (calves, quads, hamstrings, glutes, hip flexors, etc.) And you know what? When I do that, everything stops hurting for a good 20-30 minutes, until it all has a chance to lock up again. But if its getting results (and things are already less sore, which is good), then I must be on the right track.
So here's the game-plan: continue the rest/ice/stretch therapy for the rest of this week. Next week, begin easing back into WoDs, but making sure to adjust/scale/skip anything that might put ANY strain on those tendons. Push-ups and pull-ups? OK! More box-jumps? Hells no! ;)
Updates as and when they occur.