Penny, played by the talented Kaley Cuoco, is one of the most important characters in The Big Bang Theory. She is introduced to audiences in the pilot episode of the series, and is the neighbor of the socially awkward physicists, Dr. Sheldon Cooper (Jim Parsons) and Dr. Leonard Hofstadter (Johnny Galecki). Starkly different from the rest of the sitcom’s characters, Penny quickly became a fan favorite owing to the humor and charisma she brought to the series. Although not from the scientific field, Penny was part and parcel of the Pasadena crew and had a close relationship with each member of the group.