Made an awkward turn while playing and had a knee subluxation. Brief agony until I "popped" it back in and insisted I was fine. Limped around for the rest of the day, hurt for the rest of the week. For several years after, it would randomly happen again, though less severe, quicker to recover, and less frequent between incidents. Didn't bother to get it checked out since I heard any significant knee surgery would take me out of commission for some months. I'm still not sure if I'm completely over it yet. God forbid it happens to me on the stairs