This season the Big Bang gangs romantic universe expands. On the rebound from Penny, Leonard falls into the arms of Rajs sister Priya. Sheldon gets a girlfriend, or rather a friend who is a girl: Amy, a dour neurobiologist who declares herself beasties with Penny. Howard and Bernadette heat up. And so do Raj and Bernadette (at least in Rajs Bollywood daydream). All in the furtherance of award-winning genius comedy.