In the first episode Flamey the Bear is in a commercial telling the viewer "only you can prevent big vats of acid" while standing next to a vat of hydrochloric acid. When Ethel runs by chasing Steve they knock him into the vat and he promptly disintegrates, made more hilarious by his agonized gargling. The scene then cuts to a board meeting and the network president loves it.
Woody telling Malloy that he had post-traumatic stress disorder before he met him, followed by a cutaway of Woody dressed in what looks like an SS uniform with a gun to his temple in one hand and a Kermit the Frog puppet in another.
In episode 4, the rangers are on the roof trying to avoid being eaten by the army of bloodthirsty Squabbits. The Squabbits notice a helicopter but rather than try to get into it and pilot it up to the rangers like you would expect, they form together to become a helicopter.
In episode 8, Ethel swats a fly obliviously. Denzel congratulates her on her relaxed attitude about animals, but is interrupted.
Ethel: Oh look, its still alive.
(Takes out lighter and begins to chuckle evilly)
Denzel: *Under his breath* This bitch is crazy.
From the season two episode "Miracle Lake": the end where Malloy shoots Steve into the lake, which just killed off everyone who jumped in due to the medical waste.
Woody's sordid past as a pornographic actor, and his fall from grace, being unable to... perform after getting hooked on coke, and being reduced to bit parts such as the pool boys boss, and the student not kept after class.
Everyone leaving right in the middle of Woody's teary speech about his spiral into obscurity.
Malloy's line, "And that's how you direct a snuff film!" after Woody (as Rex Erection) dies doing his "Rex Rocket" stunt.
The governor building a prison around Woody's cabin after he reveals that he set her up to be blackmailed in "My Way or the Highway."
From "Trailer Park":
Bobby's best friends aimless rambling.
The Brickleberry opening being changed after Bobby Possumcods (the redneck rapist) inherits Brickleberry Park.
Steve's bumbling attempts at posing as a redneck. Made even more hilarious by Steve for some reason spouting views OPPOSITE of those traditionally associated with rednecks, in other words, liberal and non-christian. And not liking NASCAR.
Malloy setting Steve up to get raped by the rednecks ("Hey, who wants to take this guy's anal virginity?")
Denzel taking the national park magazine judge to his grandmother's birthday party in Detroit and getting him knocked out by shouting, "What's that? You watch Roots backwards so it has a happy ending?"
From "My Favorite Bear" (the episode where Steve meets his idol, Flamey the Bear):
The theme song to the "Flamey the Bear" show, where it ends with a kid getting eaten and Flamey saying, "Go ahead, kids, test me!"
Steve showing Ethel an old episode of the Flamey The Bear Show, where Flamey shows the kids how to fight forest fires, by gruesomely crushing a guy in a fire costume with a giant bucket full of water.
Steve: *laughing* I love the Flamey The Bear show!
Flamey being the epitome of a Depraved Kids' Show Host, which is even funnier when contrasted to his elegant diction. Within hours of arriving at the park, he goes on a massive drunken bender, hits up a strip club and burns it down, smokes crack in an alley (and gets Steve hooked on crack), leaves Steve to get beaten up for the things Flamey did, and has sex with Ethel before eventually dying from a heart attack after Steve yells at him for signing his album with the words, "I had fun fucking your girlfriend. Suck my dick".
Malloy tricking Woody into gradually making himself look like a giant bass through repeated plastic surgery and excessive tanning so he can win a fishing contest.
Denzel telling his assblasting master that there's no such thing as assblasting, and the master getting in a plane and crashing into a mountain. Later in the episode, Denzel and Connie arrives back at the park with a trophy, having somehow found an assblasting contest and won it.
Flamey burning the strip club bathroom with a flaming urine trick once taught to him by Wink Martindale.
Dr. Kuzniak's reason for wanting to kick Steve's and Flamey the Bear's asses ("Your crappy insurance barely paid your deductible.")
What's even better is the cause of said forest fire - Flamey's alcohol-soaked corpse that Steve dug a shallow grave for in the woods, and left with its ass sticking out of the ground, until the two resident rednecks (Bodean and Bobby) showed up and accidentally set it on fire with a cigarette.
From "Scared Straight"
The sad middle aged surburbanites that are all that remains of Denzels old gangster crew from Detroit, one of whom speaks like Mushmouth from Fat Albert as a result of brain damage from a drive by shooting.
Denzel almost being forcibly married to a convict called Meat Hammer in prison, because the warden doesn't allow premarital gay rape in his prison.
The warden also being ridiculously liberal with the death penalty, giving it to people for laughing at things he says, including one of his own guards.
Steve trying to find a replacement for Denzel for his Shadowfax cosplay for a Lord Of the Rings convention. Because he wrote "horse costume" in the Craigslist ad, everyone who showed up thought it was an ad for a furry sex party.