7. Jailhouse Rock
Jailhouse Rock is a fighting style that enjoys an almost mythical status. That is to say that we're not exactly sure if it exists. JHR was supposedly developed in, you got it, American prisons, by a group of people that have little else to do but fight and exercise. It is essentially a more formalised version of prison brawling, incorporating lots of different styles with a strong emphasis on improvisation. There are plenty of myths and urban legends surrounding the art, some think that it's probably no more than an exaggeration of some inmates' propensity to beat the living daylights out of each other, but others some think that it is a genuine discipline evolved from many African fighting styles, brought to the States during the slave trade.