In Pinky and Brain's road trip they encounter a menacing semi truck driver that continually taunts them. This is a reference to Steven Spielberg's 1971 film Duel. The driver is E.T. From Spielberg's 1982 film E.T.: The Extra-Terrestrial.
Written on E.T.'s hat is Night Skies, the original title for E.T.: The Extra-Terrestrial, parts of which ended up split between that film and Poltergeist.
References 2001: A Space Odyssey