Skateboarding
It's not surprising that skateboarding is a dangerous, if not deadly activity. Depending on the level of intensity with which you partake in the sport, your insurance may go up. Fortunately, only the most experienced skaters tend to try the big stuff, but they get hurt all of the time, too.
WEAR A HELMET
For some reason, skateboarders tend to not wear protective equipment while they skate. Whether this is either a cultural or economic issue, this is a major problem that leads to about 40 deaths per year. Skateboarding is serious stuff. If you research Tony Hawk's medical history, you'll discover why we put skateboarding on this list.