I'm so fucking glad this thread doesn't have pictures.
A couple years back we were just about to get out for lunch(for some reason we had to run to get it, we were young) I was running behind a friend and he decided to slow me down he'd close the door(think hospital doors) so he kicked it, and it starts to swing open. At that point it's so slow I don't notice it, and sprinting hard, I then proceeded to run face first(don't ask me why I ran like that) into a solid door, followed by my testicles.
Needless to say it wasn't the best experience of my life and after waking up about 5 minutes later(the only time I've ever been knocked out, and I did it myself...) I had a rather large mark on my head, but the ball pain was ridiculous.
A couple weeks back I was on my unicycle(hadn't done it in 1/2 years) and I was trying to turn. It's really fucking hard to turn on grass so I kinda end up just twisting. As I was doing this I lost my balance, the unicycle fell forward and all my weight went neck first onto the solid plastic bike seat flat against the ground. Pretty fucking sore but luckily nothing bad came of it, other than some marks.
There's others but I'm way too forgetful, the ice cube salt trick is probably up there after having a mark for weeks and pretty much being unable to hold my hand under the shower.