Four seasons in, it is still laugh-out-loud funny. Every episode, every week, says USA Todays Robert Bianco about the hit series The Big Bang Theory. Subject his conclusion to empirical analysis by watching all 24 episodes of Season Four on 3 discs. This season, the Big Bang gangs romantic universe expands. On the rebound from Penny, Leonard falls for Rajs sister Priya. Sheldon gets a girlfriend Amy, a dour neurobiologist who declares herself Pennys BFF. Howard and Bernadette heat up; meanwhile Raj is romancing her in Bollywood daydreams. Observe all the forces of attraction in this genius, award-winning comedy.