There's a lot to like -- or, if you prefer, make fun of -- when it comes to North Dakota. Take, for example, actual billboards off the highway reminding these good Midwestern folks to "Be Polite."

But the state's recent oil boom is nothing to laugh at. John Oliver devotes significant time on his Sunday show to the dark side of that boom -- repeat oil spills, a disconcerting amount of deaths on the job and lax regulations he makes the case contribute to it all.

Oh, and if you can, watch all the way to the end to see how Oliver turns one of those real-life "Be Polite" billboards on its head.

Per usual with Oliver, there's some explicit language and adult themes in the clip above. Parental discretion is advised.