I was kicked in the shin by a horse when I was about 9. I was on a pony behind it and I wasn't a particularly good rider at that point... I think my pony was annoying the horse in front and she kicked and hit me on the shin.
I think I should have gone to hospital - it swelled up and looked like I had 2 knees! But I didn't (go to hospital.. obviously I didn't have 2 knees!) - I'm pretty sure it fractured or something though. I was limping for a while and I can still feel on my shin where the bone healed.
It hurt. A lot.