So, some number of weeks ago my knee started to hurt. I don't remember doing anything specific to it. In fact, I'd been taking rather easy for a while, if I remember correctly. In any case, I haven't been able to do anything strenuous for a while [including parkour, Dagorhir, moving faster than a walking pace, leaving the ground in any way, etc.]. I don't know what's wrong with it. It's better now than it has been, but I don't think it's entirely healed yet, and I don't know how long it will be before I can do the aforementioned things without risk of injury. I guess the good thing is that it happened close to winter, so with all the cold weather I don't have incentive to do those things anyway. I just hope it's better by the time spring gets here.