Playing goalkeeper during a game a few years ago. I bounced the ball kicked at me straight downward. It hit the ground on a ditch in the grass and bounced upwards... straight between my legs. The ball was travelling very, very fast. The pain was instant, and it made me feel sick in the stomach. Funnily enough, nobody really noticed and I managed to pick the ball up, stumble with it and kick it up the field. I was in pain for around 5 minutes. Luckily the ball didn't come down my end for over 10 minutes.