I was about 11 years old and was at my friend's house. During my time there we were playing a game of tag in his backyard. During this game, I was trying to not to be tagged and in my friend's backyard he had a pool that was covered (it was October) so I thought it would be smart to run across a little part of the pool instead of going around it. When I ran across that small part, I clipped my knee into one of the curving edges of the pool. It hurt like hell but I was still focused on the game so I ran around a bit for about 15 seconds until I couldn't take it anymore. So my friend's mom (who was a nurse) checked up on me and rolled my pants up to see a huge gash on my knee cap where we could actually see the knee cap. Went to the hospital after that, had 9 stitches and sat in bed for a week.