“The Big Bang Theory” revolves around a group of five individuals residing in Pasadena, California. At the heart of the story are Leonard Hofstadter and Sheldon Cooper, who share an apartment. Across the hall lives Penny, a waitress with dreams of becoming an actress. Leonard and Sheldon are joined by their similarly nerdy and socially inept friends and colleagues: Howard Wolowitz, a mechanical engineer, and Raj Koothrappali, an astrophysicist. The humor in the series arises from the juxtaposition of the four men’s intellectual prowess and geeky interests with Penny’s practical social abilities and everyday wisdom.