In the George Lopez episode "Why You Crying?", when George and Angie tell Benny that the punished Max by barring him from TV for a month, Benny quips "Wow, a whole month without the stupid talking sponge. That's gotta hurt."
The Two and a Half Men episode "Alan Hunter, Frontier Chiropractor" had Jake explaining the show's premise to his grandmother.
The Family Guy episode, "Road to the North Pole" has Stewie venturing to the North Pole to kill Santa. Brian tries to talk him out of it by explaining that Santa isn't real. In disbelief, Stewie asks, "Is SpongeBob not real?"