Who, exactly, was Leslie Winkle (Sara Gilbert) on The Big Bang Theory, and why did she (and Gilbert) leave after season 3?

"We did the very clichéd, in the beginning, goofy blonde who says foolish things," Lorre says of the character Penny.

The Big Bang Theory series finale may have aired six years ago, but the overall franchise continues to expand. Young Sheldon chronicled Sheldon Cooper’s origins for seven seasons, and its ...