These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"Jack Sparrow", which is weird, even by the trio's standards: Michael Bolton constantly interrupting their Boastful Rap with Pirates of the Caribbean.
The entirety of Incredibad Bang Bang BANG DJ LARRY aside, "The Old Bang Bang BANG DJ LARRY! Saloon" quickly goes from a typical Lonely Island song to drunks constantly Bang Bang BANG DJ LARRY! interrupting each other. It's a parody of hip hop mixtapes in which way too many sound effects are played and the singers interrupt each other, thrown in with random screaming of the Bang Bang BANG DJ LAAAAAAAARRRRRRRrRrrRR...! DJ's name.'
"Semicolon" seems out of nowhere for the boys - with bizarre non-sequiters and crappy puns that are affixed to each sentence - but it's also a parody of Drake and Lil Wayne's style of rapping.
"Sax Man" is notable in that all of the vocals are done by guest Jack Black, rather than any members of the Lonely Island.
Also in "We're Back!", Akiva informs us that he suffers from Stinky Dick, wherein every time he urinates, a foul odor is emitted.
The Creep invokes this.
Motherlover is about two men who forgot Mothers Day and decide the best present they could give is to "fuck each others mothers". That's already creepy but then one of them says "while your in my mother, make me another brother" and plan on becoming each others step fathers.
Both "Classy Skits". One has Falcor raping Atreyu and the other has a man masturbating in front of his friends.
Weird Al Effect: Like A Boss by Slim Thug, 2 million Youtube views. Like A Boss by The Lonely Island, 82 million.
And if that metric's anything to go by, Jizz In My Pants is far better known than its inspiration - every Pet Shop Boys song ever made.
The Woobie: The title character of "Ardy Party" is a drug-addicted, disgusting, unhygienic, sexually-deviant, possibly mentally-challenged hobo who is forced by Jorma and Akiva to "rock the party" under the condition they provide him with cocaine and PCP. One of the last lines truly hammers this point in.
Akiva: If Ardy ever stopped rockin', then you know we would kill him! Roll him up in a carpet, and throw him off of a building!