Chuck Lorre's wildly successful sitcom "The Big Bang Theory" ran from 2007 to 2019, making stars out of its core cast and becoming one of the most successful entries into the genre of all time. Across that timespan, it aired 12 seasons and 279 episodes. In case you've been living under a rock or you've never turned on TBS to catch it in synidcation, here's a refresher: the show focuses on a gang of nerdy guys — Sheldon Cooper (Jim Parsons), Leonard Hofstadter (Johnny Galecki), Raj Koothrappali (Kunal Nayyar), and Howard Wolowitz (Simon Helberg) — who all work together as scientists at the California Institute of Technology, and in the show's pilot episode, roommates Sheldon and Leonard are surprised when a gregarious and gorgeous girl named Penny (Kaley Cuoco) moves into the apartment across the hall from theirs.

Eventually, the cast welcomed Melissa Rauch as Bernadette Rostenkowski (a waitress-turned-microbiologist who marries Howard) and Mayim Bialik...