Extreme sports
Extreme sports - also called Action Sports - are just not like mainstream sports. Past and present they are crawling with rebels, riders, drivers and rock stars. It's not about uniforms, coaches or scripts.
Expressing yourself through action is the key it’s an attitude, a way of life, even a religion. Once you're in, you're in for life.
Earth:
Skateboarding, Longboarding, Mountain Boarding, Sandboarding, Drifting, BMX, Motocross, FMX, Aggressive Inline Skating, Mountain Biking, Caving, Slacklining, Absailing, Rock Climbing, Free Climbing, Bouldering, Mountaineering, Parkour, Sand kiting, Zorbing
Water:
Surfing, Long/short, Body boarding, Waterskiing, Wakeboarding, Kitesurfing, Windsurfing, Cave diving, Flowboarding, Paddle surfing / Stand up paddle, Kayaking, Cliff Jumping, Coasteering, Scuba Diving, Knee Boarding, White Water Rafting, Skim Boarding, Jet Skiing
Snow and Ice:
Snowboarding, snow skiing, Ice Climbing, Snowmobiling, Snow Kiting
Air:
Base Jumping, SkyDiving, Wing Suiting, Bungee Jumping, High-lining, Hang Gliding, Paragliding, Slacklining 
Summary
The definition of an extreme sport is not exact and the origin of the term is unclear, but it gained popularity in the 1990s when it was picked up by marketing companies to promote the X Games and when the Extreme Sports Channel and Extreme.com launched. More recently, the commonly used definition from research is "a competitive (comparison or self-evaluative) activity within which the participant is subjected to natural or unusual physical and mental challenges such as speed, height, depth or natural forces and where fast and accurate cognitive perceptual processing may be required for a successful outcome" by Dr. Rhonda Cohen (2012). [4]
While use of the term "extreme sport" has spread everywhere to describe a multitude of different activities, exactly which sports are considered 'extreme' is debatable. There are, however, several characteristics common to most extreme sports. [5] While not the exclusive domain of youth, extreme sports tend to have a younger-than-average target demographic. Extreme sports are rarely sanctioned by schools. [citation needed] Extreme sports tend to be more solitary than traditional sports [6] (rafting and paintballing are notable exceptions, as they are done in teams). In addition, beginning extreme athletes tend to work on their craft without the guidance of a coach (though some may hire a coach later).
Activities categorized by media as extreme sports differ from traditional sports due to the higher number of inherently uncontrollable variables. These environmental variables are frequently weather and terrain related, including wind, snow, water and mountains. Because these natural phenomena cannot be controlled, they inevitably affect the outcome of the given activity or event.
In a traditional sporting event, athletes compete against each other under controlled circumstances. While it is possible to create a controlled sporting event such as X Games, there are environmental variables that cannot be held constant for all athletes. Examples include changing snow conditions for
snowboarders, rock and ice quality for climbers, and wave height and shape for surfers.
Whilst traditional sporting judgment criteria may be adopted when assessing performance (distance, time, score, etc.), extreme sports performers are often evaluated on more subjective and aesthetic criteria. [7] This results in a tendency to reject unified judging methods, with different sports employing their own ideals[8] and indeed having the ability to evolve their assessment standards with new trends or developments in the sports.
Classification
While the exact definition and what is included as extreme sport is debatable, some attempted to make classification for extreme sports. [9]
One argument is that to qualify as an "extreme sport" both expression terms need to be fulfilled;
" sport ": The participant has to dispose of considerable skill and/or physical ability to avoid poor execution of the actiyvity;
" extreme ": poor execution of the activity has to result in considerable risk of serious physical harm to the participant;
Along this definition, an activity such as bungee jumping may not qualify as no skill or physical ability is required to execute a good jump (i.e., avoid poor execution). A passenger in a canyon
jet boat ride will not fulfill the requirements, as the skill required pertains to the pilot, not the passengers. " Thrill seeking " might in these cases be a more suitable qualification than "extreme sport" 
Nice post bro great writeup