http://optimumtraining.ca/blog/item/sun-apr-3-2011 Found another, see comment #38. "Three months non weight bearing and six months before any real exercise." One of the comments (#42) said the following: "Was wondering if we'd see that happen on this wod. Jesse at our gym did the same thing over a year ago." Somebody else, #74, had a different injury: "I may be out too. In the second last round of box jumps I had a sharp pain at the anterior lateral aspect of my knee. First the left then the right. I can hardly walk today."
I'm sure ther are some CrossFitters lurking here. Remember: it's all fun and games until somebody gets hurt. Determine your risk/reward ratio and figure out what risks you're taking before you take them, not after you realize you've gone beyond your threshold.