Though most TV sitcoms are shot on a fairly limited schedule, their uncomplicated multi-camera setup typically gives the cast members freedom to improvise and experiment where possible, often in turn creating memorable, even iconic moments on the fly.
The Big Bang Theory is an interesting show in this regard, because numerous cast members have confirmed over the years that there's not a great deal of ad-libbing or going off-script during filming, with Bernadette actress Melissa Rauch calling the writing a "beautiful concerto that you don't want to mess up one note of."
Even so, it's only inevitable that over the show's 12 seasons and 279 episodes, a handful of unscripted and improvised gags would sneak their way in.
From actors surprising their co-stars with hilarious unexpected jokes to the cast members organically reacting to what was happening in the moment, these eight unforgettable scenes were in no way part of the original plan.
While creators Chuck Lorre and Bill Prady clearly prefer that the cast stick to the script for the most part, these indelible moments prove the power of spontaneous, off-the-cuff, reactive comedic performance...
8. Wil Wheaton Attends The Star Wars Premiere Dressed As Spock
Among Star Trek star Wil Wheaton's many memorable moments on the show, perhaps the most hilarious occurs in season nine's "The Opening Night Excitation," set against the backdrop of Star Wars: The Force Awakens' premiere.
Leonard (Johnny Galecki), Howard (Simon Helberg), and Raj (Kunal Nayyar) are joined by Wil, who has decided to dress as Star Trek's Spock, pointy ears and all, for the occasion.
The territorial Star Wars fans in the cinema naturally jeer Wheaton, to which he replies, "Live long and suck it."
According to Wheaton himself, it wasn't written in the script for Wil to wear a Spock shirt, but he simply came up with the idea and ran it by a few writers just before shooting. He said in a recent interview:
"Nobody knew that was going to happen... Only some of the writers knew, no one from the studio knew, none of the crew knew. So I come out and the explosion of like pants-s***ting laughter that comes out in that moment was genuine and it came from the entire cast and crew."
Though it was always in the script that Wheaton would visit the cinema and have an unsavoury interaction with the Star Wars fans, donning a blue shirt and Spock ears was entirely his last-minute doing.
"I don't think anybody except maybe a handful of people knew that I was going to have the ears on and be in the full Star Trek regalia."