Simple-Ton is a magazine that only appears in the episode "You Don't Know Sponge." It apparently has a ton of simple things to do, hence the title. It contains a "How well do you know your best friend?" quiz. Said best friend quiz has questions like "Is your friend left or right handed?" and "What is your friend's favorite color?"
The magazine has a green background with a gray fish on it giving a thumbs up. Above the fish, it reads the magazine's title written in yellow text and "A Ton of Simple Things to Do" written in dark green text.
The title might mean that the magazine is for "simpletons," one of the many names Squidward calls SpongeBob and Patrick. It contains quizzes like, for example, a friendship test, which SpongeBob and Patrick take, and a game where the reader makes their favorite noise.
Role in episode
SpongeBob and Patrick read Simple-Ton to answer questions about each other to see how close they are as best friends. After Patrick gets none of the answers right, SpongeBob gets the impression that Patrick knows nothing about his best friend anymore and enters a depressed state.
This is SpongeBob and Patrick's favorite magazine.
The name of the magazine is an obvious play on the word "simpleton," which refers to a gullible or foolish individual.