Basically, Bevis and Butthead. Or, rather, Gork is a blood-crazed berserker who tries (emphasis on tries) to strategically place himself at a point before he starts swinging and spraying and Mork is a Kommando who likes to hack the bodies of his foes apart long after they have been slain. At least, that's how I always got it.
i agree with callum about the orks and as for orks being stupid soccilay they are just misunderstood. they have a complicated social structer much like politics. if you get pepole to like you you get more important.
in ork society everyone knows their place. compared to the other races ork politics are exceptionally streamlined: "i'm bigger dan you so you'z my subordinate, if you don't like it i'll kick your teef out."
our own political institutions could learn something if politicians run the risk of having their teeth kicked out :)
To be fair, GorkaMorka happened as much because Orks like fighting too much as it did because of religion. If you leave Orks alone in an area without a 'stable' leader for too long, they will inevitably start trying to kill each other out of boredom. This is the main reason they haven't curbstomped the universe yet.