"Cat-Astrophe" gives us this gem: At a retirement home, Cosmo and Wanda are trapped in a butterfly net by an Alter Kocker who shows them pictures of his grandchildren. At one point, he holds up a souvenir shirt reading "I cut a rug - and a little something else - at Ruben and Saul's Bris!"
According to a billboard, the mascot of Adrenaland is a pill known as Phen-Phen Phil. Phen-Phen is the commercial name for fenfluramine/phentermine, which was used as anti-obesity medication until it was shown to cause potentially fatal pulmonary hypertension and heart valve problems. While it is more of a Parental Bonus joke, how often do you hear or see a drug reference on a Nickelodeon cartoon that was made after 1999 (or, at all)?
One example from the Tom Sawyer episode:
Timmy: He can turn planets into plants. He can turn gravity into gravy. Wanda: He can turn Uranus into... Oh my gosh! We've got to stop him! Cosmo: What?! I don't get it—what's the threat?!
And the Adam West / Catman as a kid episode, where he repeatedly latches onto people legs in an... "affectionate" hug. Leading to this line:
Timmy: "So he can stay the night?"
Timmy's Dad: "Sure! He's part pet! But he gets 'affectionate' with my leg, he's off to the shelter!"
And, in a later part of the episode(where Catman is returned to normal), we get this.
Timmy's Dad: Sure, we love Adam West. He's part legal guardian and part pet!
Timmy's Mom: And he's so affectionate!
And Timmy's dad gets pissed when Adam does this to Timmy's mom.
It gets weirder when the two glance at each other, almost embarrassed.
In Power Mad, Timmy reaches a level in a virtual reality game that he describes "looks like an underwater version of my Aunt Gertrude's house." A crab version of said character suddenly comes in, saying she "wants to pinch those chubby cheeks" of Timmy's. He then replies, saying "I hope she means my face."
Wanda later gives that line a Call Back, when Timmy wishes for "cheeks of steel."
In Escape from Unwish Island, Timmy (after noticing his parents are gone) decides to do everything he ever wanted(roller coaster in the house, etc.)
Timmy: Finally, every ten-year-old's dream! A room full of supermodels!
Timmy, however, promptly asks the swimsuit clad models if they can bake cookies, but we hear Cosmo later mention something about bouncing on the bed with the supermodels.
We get a reference to anti-racism in "Father Time".
Cosmo: (referring to a foot race) This is a good race!
70s!Wanda: We think ALL races are good, man.
70s!Cosmo: We don't judge.
In "Operation FUN" Crocker gets hit with an exploding rocket with an "F" on it...or an F bomb.
"Meet the Oddparents!" is an episode designed to get past the radar.
In "Farm Pit" Cosmo says he stole slippers from a "sleeping munchkin" then when we cut to Cosmo stealing slippers of a guy in an area surrounded by crime scene tape, and he says "at least I think he was sleeping", meaning that Cosmo looted from a dead guy.
In "DinkleScouts", Timmy's Dad comments that if he takes a group of boys to the theater in his troop leader uniform he'll get arrested, implying he means he'd get mistaken for a pedophile.
In "Genie Meanie Minie Mo!", the substance smoof is obviously a parody of hemp.
Let's not forget the "magic weenie" joke from "I Dream of Cosmo".
In "Cosmo Con":
Cosmo's wide smile when Britney Britney rubs him all over her face after she mistakes him for a towel.
Mr. Turner wants to celebrate "proving his masculinity" in getting his wife "back" from Crocker, so he tells Britney Britney to "hit it", obviously meaning to sing. Mrs. Turner then complains that he never tells her to "hit it", and angrily tosses Britney out of the house.
And the consistent use of the word "sexy" throughout the show. Juandissimo says it most often, but Jorgen (in "Fairy Fairy Quite Contrary") and even Timmy (in "Abra-Catastrophe!") also use the word.
Does no one remember the picture of crossdressing Crocker from "Information Stupor Highway" that gets sent worldwide via email? Timmy's dad sees it on Timmy's computer screen and hints at him watching porn.
The title of one of the later episodes: "Crock Blocked". Jesus Christ Nickelodeon...
In this very episode, there's a scene where Timmy finds Crocker hidden in his bed in a cockroach costume. Mr. Turner arrives to hit the "crocker-roach" in the eggsac. This joke repeats itself when he thinks Crocker is a chicken ghost.
That's nothing compared to these episode titles: "Who's Your Daddy?" (Timmy wishes he had A.J.'s, Chester's, and Sanjay's fathers) and "Home Wrecker" (Timmy wrecks Vicky's house so she'll get blamed for it).
Throughout the episode "Fairly Odd Baby", Poof's unidentified sex becomes a running gag, and Timmy, Cosmo, and Wanda keep wanting to "check" (which they do by almost peeking under his diaper). In the end, they never find out by means of what Poof's got down there, but by the fact that he suddenly has a water squirter, in which Timmy concludes it's a boy because "boys love water squirters".
Mr. Birkenbake, the New-Age Retro Hippie teacher at Dimmsdale Elementary School, has a name that's a subtle portmanteau of "Birkenstock" (a type of sandal stereotypically worn by hippies and butch lesbians, but mostly hippies) and "bake" (slang for smoking marijuana).
Quite a few fly by based on a gag in "Anchors Away" where Cosmo is wearing a skirt:
Most of the subsequent slips are related to his "cha-chas" being referenced: "I landed on my cha-chas!" "Ouch, not the cha-chas!"
In "The Past and the Furious," Sparky and Timmy are repairing damage to the timeline. After they repair the first part, Timmy says that it's "fixed." Sparky replies with...
Sparky: (while covering groin) Don't EVER say "fixed" to a dog, Timmy!
There are actually a lot of neutering jokes, most of them about Vicky's dog.
In "Mission: Responsible" Timmy says he doesn't want Mama Cosma to babysit because she pinches his cheeks way too hard. Cosmos adds "We are a hard cheek-pinching family. Front and back!"
In The Big Problem upon seeing the older Timmy, Vicky blows a loud whistle and beats him up before throwing him out of the house. When it happens again on the street, two cops show up to arrest Timmy calling him "one creepy adult". It's clear 16-year-old Vicky thought of some not-so-nice images of the older Timmy and was blowing a rape whistle.