Curious to see what they’ve been up to since the cameras stopped rolling?

There are a lot of great episodes of "The Big Bang Theory," but which ones are the most rewatchable?

Add Yahoo as a preferred source to see more of our stories on Google. Sheldon knocking on a door on The Big Bang Theory - CBS "The Big Bang Theory" featured many recurring habits that defined Sheldon ...

"The Big Bang Theory" featured many recurring habits that defined Sheldon Cooper (Jim Parsons), but few were as consistent as his practice of knocking on doors three times — most often when visiting ...