The Big Bang Theory changed its winning formula after 3 years, and thankfully, the gamble paid off. Chuck Lorre and Bill Prady's comedy remains as one of the most popular sitcoms of all time. Aside ...

Add Yahoo as a preferred source to see more of our stories on Google. Michael Yarish/Warner Bros. Amy Farrah Fowler (Mayim Bialik), Sheldon Cooper (Jim Parsons), Leonard Hofstadter (Johnny Galecki) ...