Thanks Julie and others. I did it by jumping from 4-5 feet up onto a gym pad. Landed awkwardly on one foot because I jumped from a wide stem. My ankle dug into the pad and rolled and that displaced my knee enough to rupture the ACL, tear the medial meniscus, and sprain the lateral collateral tendon.
My repair is an allograft, which means it came from a cadaver. I've decided this means I have a ZombKnee, and of course have been careful to check the organ donor box in the driver's license form, since now I'm sorta obligated to give back, if you know what I mean.
I know of two other climbers who have done almost exactly the same thing in the last year. I suspect that cushy pad landings, wonderful as they are for total wipe-outs, may be more dangerous for the knees than something firmer.
Rehab is a long and boring process, as some of you know all too well. I do it religiously. If there are no setbacks, I might be able to do at least some easy outdoor climbing this Fall.