 In the episode "The Ornithophobia Diffusion", when there is a delay in watching "Star Wars" on Blu-ray, Howard complains, "If we don't start soon, George Lucas is going to change it again" (referring to Lucas' controversial alterations to the films) and in "The Hot Troll Deviation", Katee Sackhoff of "Battlestar Galactica" appeared as Howard's fantasy dream girl.The characters have different tastes in franchises with Sheldon praising "Firefly" but disapproving of Leonard's enjoyment of "Babylon 5".With regard to fantasy, the four make frequent references to "The Lord of the Rings" and "Harry Potter" novels and movies.