Orkhammer
Otherwise known as WaaaghHammer. The basis of Orkhammer stories is that Orks have somehow manage to infiltrate a major faction to such a degree that pretty much everyone believes that they are just really big and green members of their side while a non-ork narrates. Whether or not someone realizes the truth and tries to point it out to no avail depends on the individual story. The naming style typically involves slapping the three letters of Ork into the name of the faction, typically in the front but it all depends on which would be funniest.
Deffwotch
Main article: Deffwotch
Deffwotch is a Rogue Trader campaign in which all players are Orks posing as a Deathwatch Kill Team. And just in case that alone wasn't hilarious enough, gamemaster Shas'o R'myr tosses in some of his own fluff free of charge.