What happened to my knee, I mean.
See, part of the curse of being tall is that your feet hang off the edge of the bed rather often.
Apparently, Monday night I slept on my left side, with my left leg straightened to the point that the knee was locked out straight. And the toes of my left foot were hooked over the end of the mattress, holding the leg in place. And then just add slight downward pressure from my bent right knee to the side of my hyperextended left knee for a few hours.
Not a lot of pressure, but steady pressure pushing the joint in a direction it's not supposed to go, with the leg locked in place. While I slept.
It feels a little better today. And the aspirin this morning is a lot more effective than the aspirin yesterday morning, but I'm still going to limit my activities today to a quick range trip.