Fanboy and Chum Chum are Reality Warpers.They had superpowers in "Brain Freeze" because they believed they did, not because of their underwear. In "Fan Vs Wild" the roof of the Frosty Mart became a frozen wasteland because they were really getting into their "mountain hiker" game (also the reason there was a pack of wild burritos there). Their separation in class tears a hole in reality because they believed it would.
Fanboy was adopted and named by Oz, and Chum Chum was adopted afterwards.If memory serves, in "Dollar Day" Oz referred to FB and CC as his "charges", i.e. people in his care. Since Fanboy and Chum Chum met in kindergarten(?) (reference: "Fan Vs. Wild"), it may be that Chum Chum was adopted into the family after Fanboy, and that may be why Fanboy is the leader of the duo, as well as having the Fanlair named after him and the door in his likeness. Seeing as Oz is such an obsessed fanboy of superheroes himself, it doesn't seem ridiculous that he would give such a name to a child.
Fanboy and Chum Chum will reference the Internet Backlash of their show soon.You just know the boys will!
The name of Oz's mom is Ozma.A Wizard of Oz reference (supposedly Oz is the title of a male ruler of the land of Oz, and Ozma is the title of a female ruler of the land of Oz), and "Ozma" also sounds like "Oz's ma".
Kyle is possessed.He hangs out with Fanboy and Chum Chum in some episodes and regards them as his friends, but when they annoy him in a clip of "Tooth or Scare" he tries to feed them to his pet monster. He acts reasonable and level-headed sometimes, and other times he does dark and sinister things; sometimes he laughs maniacally or his eyes glow red. It's left somewhat ambiguous as to whether he is good or evil. Kyle has described himself as a "practitioner of the dark arts", and is capable of summoning strange creatures, but he's also an Inept Mage. His flip-flopping between good and evil could be accounted for if perhaps a summoning went wrong and caused him to become possessed by an evil being which only makes its presence known some of the time.
Chum Chum is a coprophilliacSelf-explanatory whenever the school's janitor is around.
Fanboy and Chum Chum are part of the militaryHenceforth, why they mention the internet in a time of 8-bit games.
The reason Adventure Time aired on Cartoon Network and not Nickelodeon is because...Nickelodeon ended the contract with Frederator for letting this show come into existence. Because the show frequently uses toilet jokes and obscure forms of humor, the fellas at Nickelodeon felt it was not safe to keep Frederator actively producing shows because they feared that Frederator might make another bad one. So that is why Frederator aired Adventure Time on Cartoon Network.