Combatives is term for the hand-to-hand training and techniques employed by the US Army. What's particularly great about it is that it uses a lot of BJJ and submission grappling. I watched a Discovery documentary TV show about it, so, as you can expect, I'm pretty much an expert on the subject.
Check out the video below featuring 2 of Robson Moura's black belts, Josef Manuel and Andre Ushirobira as they roll with Combatives students during a course. This is a some ridiculously smooth Jiu Jitz. This is another great illustration BJJ's relevance, not just as a sport or element of the MMA game, but as a significant method of self defense. Word.