"Imaginationland" drew over 3.4 million total viewers and was the most watched program in all of television for Wednesday night among men aged 18 to 24 and 18 to 34, and was also ranked #1 in cable among persons aged 18 to 49.

Production for "Imaginationland" began in July of 2007. That's nearly three months before the actual airing of the episode, something that's uncharacteristic of a show where episodes are produced in one week or less. The original intention of the story was to make it into a feature-length film.

As of March 11th, 2008, The Imaginationland DVD was released.

In each episode of the "Imaginationland" trilogy, Cartman appears dressed as a figure of authority. In this episode he is dressed as a Sultan.

Cartman: I believe a certain someone is supposed to put a certain set of balls in their mouth.

Visual: Saving Private Ryan

During the terrorist attack on Imaginationland, Stan sees the events in slow-motion. This scene is similar to that of the opening scene from the 1998 Academy-Award-winning film Saving Private Ryan, directed by Steven Spielberg.

Imaginationland Mayor: They are coming.

As the barrier that separates the two sides of Imaginationland begins to fall apart, the Mayor's line is a possible reference to that of Gandolf's line in the film The Lord of the Rings: The Fellowship of the Ring (2001) before the oncoming battle in the Mines of Moria.

Visual: Inhabitants of Imaginationland

Some of the characters living in Imaginationland have appeared in previous episodes. Najix, the alien from "Cancelled," appears in the form of an ice-cream crapping taco. There's an Underpants Gnome from the season 2 episode "Gnomes," as well as members from "The Super Best Friends." All the original members appear except Mohammed and Jesus.

Visual: Mel Gibson

When the government seeks help from Mel Gibson, his appearance has remained unchanged from the season 8 episode "The Passion of the Jew." He is still shirtless and in his underwear.