“The line “I have come here to chew bubble gum and kick ass, and I’m all out of bubble gum” was ad-libbed by Roddy Piper. According to director John Carpenter, Piper had previously written the line in his notebook of potential verbal bits during his wrestling career. He shared the notebook with Carpenter, and they agreed that this particular line fit the character and the film perfectly. Piper went on to use it at a wrestling match.” (from IMDB)