This will probably be an on going series, since there's this misconception that a) wrestling isn't technical, and is all brute force and ignorance and b) not all grappling is BJJ!
There's already much debate and much confusion over what Matt Hughes choked out Ricardo Almeida with during Saturday's match at UFC 117. BJJ fans are coming up with crazy name amalgamations (I've even seen a 50/50 guillotine-anaconda used - really!?) or just the 'Hughes' Choke'. Judo guys have said it's a Katagatame, but all this means is 'arm triangle' and applies to any position you can get an arm triangle from. Ex-pro wrestling personalities Jim Ross and Paul Heyman called it a front facelock, which is also incorrect (and I'll post exactly what a front facelock is at a later date).
Quite simply it's an old wrestling move, and as both Hughes and Chuck Liddell have said is an arm-in front headlock which was often illegally applied during matches to cause a choke.
When legally used in wrestling it's an excellent control point that allows for setups to takedowns such a single leg takedown on the same side as the head in the above picture.
You can also arm-drag of sorts and take the back - in the above picture you would go counter-clockwise.
However I'm sure what everyone here is interested in is how it can be used as a choke.
(Dave Schultz illegally chokes a guy at the 1984 Olympics. In some areas the arm-in headlock choke is known as the Dave Schultz Headlock. The Schultz brothers became notorious for chokes and Sakuraba style Kimura's aka Double Wrist Locks in wrestling).
As explained in this gif, Hughes immediately goes for an arm-in front headlock control. It's difficult to tell from this angle but he may have Almeida's chin in a chinstrap grip while is other hand looks like it might be going to block Almeida's knee to stop him standing back up.
Fairly self explanatory. It's difficult to see what grip is being used, but it's likely a C-grip / finger-grip or a gable grip / palm grip. Hughes maintains a straight back throughout.
Hughes tripods again to put more weight on Almeida's neck and shoulders, rotating Almeida's head enough for the blade of his forearm to compress the carotid artery. Hughes shifts his hips down to add more pressure but Almeida is already out and the ref is already moving in to stop the fight.
As you can see, the sub wasn't pulled off with brute force as a lot are reporting, but was largely down to Hughes' knowledge of weight distribution, leverage and hip movement which comes from years of wrestling.
Thanks for reading.
Josh Barnett has since put a video on Youtube showing more details on how to get the choke.