Here is an old but mysterious style from Japan. Ninjitsu! Back in the 80's this was a very popular martial art. It was popularized by the first American Ninja: Stephen K Hayes.
He wrote all kinds of books about this art. There are many arts within ninjistu. Tai-jitsu is the unarmed style of the art. He is an interesting man and you can learn more about him here: http://en.wikipedia.org/wiki/Stephen_K._Hayes . He started training way back in 1975 in Japan and then came back to the US and started teaching. However he only taught a few students. It was not until recently that he started teaching the public.
So where can you get the clothing that they wear? It looks pretty cool. Go to http://www.authenticninjaclothing.com/more-ninja/ninja-clothes/ and see the different kinds available.
See more of this ninja art: