Keith Carradine has appeared in three episode as Penny's father, Wyatt, first in Season 4. Katey Sagal, who played the on-screen mother of Kaley Cuoco's character in the 2002-2005 sitcom 8 Simple Rules, has appeared as Penny's mother in one episode of The Big Bang Theory. Jack McBrayer has appeared in one episode of The Big Bang Theory as Penny's brother, Randall.
The Big Bang Theory is an American comedy television series created and executively produced by Chuck Lorre and Bill Prady. Like the name of the series itself (with the exception of the first episode "Pilot"), episode titles of The Big Bang Theory always start with "The" and resemble the name of a scientific principle, theory or experiment, whimsically referencing a plot point or quirk in that episode.
Initial reception for the series was mixed. The review aggregation website Rotten Tomatoes reported a 52% approval rating for the first season based on reviews from 23 critics, with an average rating of 5.18/10. The website's critical consensus reads, "The Big Bang Theory brings a new class of character to mainstream television, but much of the comedy feels formulaic and stiff." On Metacritic, the season holds a score of 57 out of 100, based on reviews from 23 critics, indicating "mixed or average reviews". Later seasons received more acclaim and in 2013, TV Guide ranked the series #52 on its list of the 60 Best Series of All Time.
^ Jump up to: a b Kondolojy, Amanda (October 12, 2014). "'Gotham' Has Biggest Adults 18–49 Ratings Increase; 'Gotham' & 'Red Band Society' Top Percentage Gains & 'How To Get Away With Murder' Tops Viewer Gains in Live +7 Ratings for Week Ending September 28". TV by the Numbers. Archived from the original on October 16, 2014. Retrieved October 13, 2014.
When Leonard receives a braggy Christmas letter from his brother, he feels bad about how little he and Penny have achieved in the past year. Leonard wonders if he and Penny should be thinking about the next step after two years of marriage, like buying a house or having a baby. Penny tells him she wants to do all those things someday, but she has a bunch of stuff she would like to do first.