Ron Lester, who basically plays the exact same character he was in Varsity Blues (like Gleason above). They even have a running countdown of how many concussions he has left to go before the movie ends, in reference to his Blues character's arc, which was about him being nearly killed from having too many concussions.
Molly Ringwald as the Flight Attendant. Her lines are coated in irony, at one time even saying "Fucking Teenagers" and scoffing. At one point Jake quotes Pretty in Pink to Janey, to which Janey asks "Are you sure?" and Ringwald replies "Trust me".
Big Screwed-Up Family: Jake's family: his dad wants him to go to the same college as him and have the same job as he, his mom is willing to sleepwith him to complete the illusion, and his sister is endlessly trying to have sex with him. At first, it seems as though they are spoofing Cruel Intentions and that they are Not Blood Siblings until she affirms "only [related] by blood".
Brick Joke: The conjoined twins really do make up one decent chick... they wind up becoming Prom Queens.
Also, the albino hippy at the start of the movie appears during the closing credits, this time mentioning that her retinas have burned out and she needs help... in song.
During the film The Breakfast Club, a piece of pimento loaf is tossed onto a statue. This movie's parody of that movie is filmed in the same library, and starts with said piece of pimento loaf finally falling off of the statue.
Katherine: So what if we have the same mother?/Tonight I'm gonna fuck my brother!
Butt Monkey: Poor, sweet Ricky. He tells Janey that he's in love with her to her face, only for her to completely ignore him. Ends up broken and battered trying to beat the Big Man on Campus to the Airport, as he gets hit by a couple dozen cars. Ends up starting the Slow Clap... which gets him beaten up again.
The Cameo: Molly Ringwald, Melissa Joan Hart, Sean Patrick Thomas. Joan Hart's can be seen as a parody of Sarah Michelle Gellar's cameo in She's All That.
Catch Phrase. The Token Minority lampshades this: "I'm just supposed to smile, and stay out of the conversation, and say things like 'Damn!', 'Shit!' and 'That is whack!'" Later, there is this brilliant exchange:
Token Black Guy: *clears throat*
Other Black Guy: what?
TBG: I'm supposed to be the only black guy at this party.
Contrived Clumsiness: Parodied. The heroine who already wet from jumping the pool, and the villainous Alpha Bitch, sarcastically feigning clumsiness, spills a bottle of WATER on her. The heroine reacts with humiliated tears.
Made even sillier by someone in the background shouting "That's gonna stain!"
Crowd Song: The one before prom. Lampshaded immediately afterwards: the participants look at each other and leave awkwardly.
Dawson Casting: Deliberately so. Most of the cast were in their twenties at the time, likely to parody high school films. Although Lacey Chabert, Chyler Leigh, and Chris Evans were fairly close at 18, 19, and 20 respectively. Also spoofed with the parody version of Drew Barrymore's character from Never Been Kissed, who looks like she's in her 70's but nobody ever seems to notice it.
Expy: Aside from the Stock Characters already mentioned, Ox is a blatant expy of Oz, what with only being a single letter off on the name, and having the same attitude towards sex and love that Oz ended the first movie with.
Europeans Are Kinky: Parodied with Areola, the foreign exchange student who is constantly nude.
Lampshaded with the "Dainty Girl", in a Shout Out to the bathroom scene in Detroit Rock City (except with an unending stream of poo). As an added bonus, an English professor is heard berating today's youth for their crude taste in humor, right before the ceiling collapses and showers him in the girl's excrement.
Hollywood Homely: Parodied In-Universe. Jake, the popular jock, has to make Janey beautiful because... you know, she's hideous! Just look at the glasses! And her ponytail! And the paint-covered overalls! And this in comparison to an albino guitarist, a hunchback, and conjoined twins.
Informed Ability: Janey's "artistic talent" is essentially just drawing kindergarden-level stick figures.
Meta Guy: Most everyone, but the two most consistently aware of the genre conventions are Malik and the unnamed tour guide played by a pre-How I Met Your Mother Josh Radnor "Who would have guessed this school was filled with professional dancers."
Non-Specifically Foreign: "European" is about as close as your gonna get with Areola. While saying "grazie" when Janey complimented her backpack might lead you to Italian, her accent changes with every scene.
Silent Whisper: Austin whispers into Janey's ear, causing Jake to launch into a hysterical confession. Austin then explains to Jake that what he actually whispered into Janie's ear was that Jake was about to launch into a hysterical confession, thus reaffirming everything he just whispered into her ear.
Sophisticated as Hell: The Token Black Guy is revealed to be this, delivering a very deep insightful speech to Jake near the end. When Jake pauses to thank him, then dashes out abruptly before he can reply, he says only one word: Mother''fuck''er.
Spit-Trail Kiss: Between Jake's sister and an elderly woman pretending to be a teenager at the Wild Teen Party. Probably one of the grossest ones ever recorded on film.
Stock Character: This movie goes out of its way to include as many as possible usually directly referencing the more famous examples from this genre. Lots of Lampshading too.
Unusually Uninteresting Sight: Areola again — outside of her introduction, and the other naked girl at the party who complains that she copied her outfit, no one notices her walking around in the buff.