"Oi gitz, how do you use this zoggin' interwarp?!"
"You'ze already usin' the interwarp, ya grot!"
Gork & Mork are the Gods of the Orks. Gork is cunningly brutal (will hit you when your looking), while Mork is brutally cunning (will hit you when your not looking).
Gork and Mork came into being when the Orks had enough collective psychic power to manifest in the Warp, in a similar way to the Eldar gods. The difference is that the Orks can actively call upon help from their Gods, building great tributes to them and being imbued with their power. Gork is favored by the common Ork for his directness and brutality, while more ambitious Ork commanders favor Mork to grant them the cunning they need to overcome enemies and rival Orks.
Gork & Mork mostly argue with each other over the Warpchat; Gork in particular is so dense that he asks how to use the Interwarp despite already being on it. Decius has also called them "literal mushrooms".