Pat has posted a couple of videos on this guy: Robert Sharpe. The videos are great to watch, very informative in their own right, but (as Pat said on his blog) if you substitute aiki or aikido into his discussion it comes out as a great lesson for us aiki guys. I wish there was more to find on this guy, i like his personality and his philosophy on what he does and the world around him is definitely worthy of note.
Enough of my gabbing, here's the one i wanted to show first(since that link apparently has every freaking one of them). This one is part of the interview that relates who he is and what he's done:
And this is an example of one that you can throw aikido into what he's talking about, he's talking about tai chi push hands and randori can be interchangeable with much of it:
Anyway, i like the videos ( reiteration ) and i think you should go watch them all. Yes even the capoeria ones.