Extreme ironing is a kind of sport where people take an iron and an ironing board to remote, difficult, and sometimes dangerous places, and then they iron their clothes. It's similar to regular ironing at home, but instead of doing it in a comfortable, safe environment, people do it outdoors, in places like the top of a mountain, underwater, or even while skydiving.
So, imagine you like to iron your clothes, and you also like adventure and doing challenging things. Instead of ironing your clothes at home, you pack an iron and an ironing board, and you go to climb a huge mountain. When you reach the top, you take out your iron, plug it in (if you can), and iron your clothes. You may be standing on a narrow ledge, and it may be very windy, but that's part of the challenge. You're not just ironing your clothes; you're doing it in a difficult and exciting environment.
Extreme ironing has become popular around the world, and people come up with creative and risky ways of practicing it. Some do it while skiing or snowboarding, others do it on a surfboard, or while hanging from a cliff. Some extreme ironers even organize competitions, where they try to outdo each other by ironing in more extreme and dangerous locations.
In summary, extreme ironing is a sport where people take ironing to the extreme. They iron their clothes in remote and challenging places, and they do it for the thrill and excitement of combining an ordinary activity with an extraordinary location.