Dirt bike racing, bungee jumping, paragliding, skateboarding. Cheese rolling, extreme ironing and going over Niagra Falls in a barrel (yes, really ). There's all kinds of crazy and not-so-crazy extreme sports.Here's your chance to get the facts.It's OK doing extreme sports when you want to, but what about when you HAVE TO -- to survive Read "The Climb" and find out.Finally use the Word Check to make sure you know your kitesurfing from your skysurfing.