The Big Bang Theory: 8 Moments That Were Completely Unscripted

And finally, we have Penny's bizarre absence from the show for two episodes and the means through which she made her return.

Penny doesn't appear in the early season four episodes "The Desperation Emanation" and "The Irish Pub Formulation" due to Kaley Cuoco breaking her leg in a horseback riding accident.

But rather than contrive an on-screen excuse for Penny's absence as sitcoms do all the time when actors suffer injuries, the writers simply decided not to address it at all. This also led to Amy and Bernadette not appearing for the two subsequent episodes due to their planned scenes with her.

Penny returned in "The Apology Insufficiency," but because she was still recovering from her leg injury, the production team had to figure out a way to have her perform her lines without drawing attention to it.

And so, they decided to have Penny be randomly promoted to bartender at The Cheesecake Factory, where her legs wouldn't be visible behind the bar, and in the episode's final scene she only appears sat down where she doesn't need to move.

You'd admittedly never think about this without knowing it, but the writers evidently had to change things up on the fly to accommodate Cuoco's unfortunate injury.