Mixed Martial Arts (MMA) seems to have taken the top spot in popularity over other contact sports such as boxing. It's very big in North America, Europe and even Africa. As the name suggests its a combination of various disciplines; boxi, wrestling, Muay Thai, judo, karate, jujitsu, etc.
I have seen 100,000 seater stadiums sold out for fights. Pay per view matches on American cable tv can go for as much as $80 per fight if not more.

Is anybody else a fan of this sport?