Martial Arts have been around since there was a need for conflict resolution. The study of conflict and how to gain the best advantage from conflict are the basic building blocks of Martial Arts.

There are several schools of martial arts, each with it's own flavor and character. Some examples;

Karate
This martial art was originally designed for unarmed peasants to take on fully armoured soldiers. Strikes are linear and extremely strong, as practicioners were not expected to get a second hit.

Judo
Literally translated as the soft way, Judo is best known for it's throws and joint locks. Originally based on Ju Jitsu, Judo is now an Olympic Sport.

Aikido
Inspired by Samurai in Japan as the combat art of last resort after being disarmed. This art promotes harmony between you and your opponent, and almost all moves are reactions to attack.

Boxing
In it's many forms, boxing is probably the most universal martial art. Many cultures consider fighting on the ground to be uncivilised, so boxing emphasizes punching.

Capoera
Masked as a dance, Capoera was a martial art taught between slaves in Brazil. Because the hands were almost always shackled, Capoera uses wide sweeping kicks and handstands.

Ninjitsu
A martial art mostly praticed by Americans.


There are many other forms of martial arts.

An art form primarily associated with combat. Like dance, combat can be formalized from an instinctive act of belligerants into a set of rituals, techniques, and forms.

It is worth noting that the Japanese consider all art forms associated with the samurai class (collectively bushido) to be martial arts, despite many of them, e.g. go-do, or the tea ceremony, having a dubious connection to combat at best.

A fairly comprehensive list of specific martial arts can be found in that node.