Running is sort of a safe sport (besides overuse or muscular injuries). Other sports are not so safe. Some activities probably should not even be called sports. Have you ever seen wingsuit base jumpers? These guys are completely nuts but they can really fly! Check out this video.
I remember seeing a show on these guys a few years ago and one jumper misjudged the bridge he was jumping under and killed himself so this is not the best sport to try, but it is simply cool to watch when they get it right! I think I will stick to my running!