When I was a kid, I had a freak accident while playing a heated game of
"Red Rover" when I fell down and my knee split open on the corner of an unseen cinder-block laying off to the side of our lawn. I distinctly remember not feeling much pain at first, and even thinking how oddly white the open gash in my knee looked before the shock wore off and both the pain and the bleeding started. Ended up needing 10 stitches, and because I couldn't bend my knee without risking re-opening the wound or tearing the stitches, I had to hobble along with a crutch for almost a whole month that summer.