According to Arthur in "Double Dare," "Crazy Bus" was recording by "some guy no one ever heard of" in his bathroom.
In "Arthur and the Big Riddle," one of the riddles is, "I am a nut that has no shell," to which the answer is "doughnut." But cashews are one of many nuts that do not have shells.
While this is true, maybe all answers have to be clever riddle answers.
The second story of the episode, "Double Dare," bears the same name as a 1976 game show that Alex Trebek (Lebeck) once hosted.
In "Arthur and the Big Riddle," Buster writes down the address for the Riddle Quest studio without looking at the TV.
In "Double Dare," Buster believed in dares, but in "Arthur and the Daredevils," he says it would be stupid for someone to do something just because someone dared them to.
In "Double Dare," just as Arthur's friends are leaving his room, Brain's shirt changes from dark brown to light brown.
In "Arthur and the Big Riddle", Arthur doesn't know what Riddle Quest is. But seeing as how Buster watches it all of the time and he and Arthur are always together, it's very unlikely that Buster wouldn't have mentioned before.
Not to mention that Riddle Quest is a children's game show, so someone had to have mentioned it before. And that it's been on the air for more that weeks.
Alex Lebeck: (as an old adult) I'm purple and I go "Mmmm". What am I?
Arthur: (as an old man ringing the bell with a cane) Aw, I forget.
Alex Lebeck: Huh? Oh, so do I. Oh well, we'll give it to you anyway.
(Old Arthur dances after being won while the audience applauds.)
This is the final season with Michael Yarmush voicing Arthur. His voice is noticeably deeper at this time. The Brain is also now recast to Steven Crowder and sounds significantly different from his previous voice actor.
Charlotte Bickles' name is similar to Charlotte Pickles' name from Rugrats.
Arthur's dream in "Arthur and the Big Riddle" is a parody of Alice in Wonderland. Right down to the style of illustration.
Riddle Quest's Alex Lebeck is based off Alex Trebek, host of the game show Jeopardy.