In "Idiot Box" Squidward pulls a sombrero out of a hat box and says, "Why haven't I worn this yet?" Squidward is seen wearing that same sombrero in "The Camping Episode" later in the season.
Patrick yells out "I am the Lizard King!" while in the box. This is a reference to Jim Morrison from The Doors who called himself the same thing.
Although This Episode Premiered In 2002 It Was Made In 2001 According To The Credits