One of the more famous episodes, purely on how strange and off-the-wall the story becomes, even in the context of the show.
Ed appears in Eddy's bedroom late at night asking random questions about everything he sees, bothering Eddy all night long. In the morning they go to Double-D's house to find him disassembling an antique radio in order to understand how to works. Eddy then gets an idea: if they knew how everything worked, they'd be famous and get rich.
After taking apart a washing machine and Rolf's chicken coop (with Double-D taking notes all the while), things start to get weirder and weirder- a tree is now flat as cardboard. Ed cuts a hole in thin air. Eddy actually eats the sun and turns it into the moon. From that point, the whole world becomes a cross between a Dali painting and the Milkman Conspiracy level from Psychonauts
, becoming more and more random and nonsensical until finally Double-D's notes get scattered and the whole world goes back to normal.
Naturally, it's never brought up again
This episode contains examples of: