The Big Bang Theory's Unaired Pilot, refers to the original pilot made for the 2006-2007 season that was not picked up by the network, thus it was never aired. Only Johnny Galecki and Jim Parsons were in the cast, and the female lead, Katie, was envisioned as "a street-hardened, tough-as-nails woman with a vulnerable interior". Katie was played by actress Amanda Walsh. They also had a female friend called Gilda (played by Iris Bahr). The show's original theme music was also different, using Thomas Dolby's hit "She Blinded me with Science".
Leonard and Sheldon encounter a young woman named Katie crying on the curb, having been left homeless by a break-up with her boyfriend. Leonard, despite Sheldon's objections, invites her to dinner and then to stay a few days at their apartment. She is abrasive, sexy, hard, and sarcastic, but she softens a little when she discovers that the guys aren't trying to get something from her. In the end, she decides she'll crash at their place for awhile.
The episode opens with Leonard sitting in the sperm bank waiting for Sheldon to finish his deposits, which he eventually finished using a magazine of women with big butts (his fetish). At the desk, after annoyingly finishing the receptionist's crossword puzzle, they are told that they won't be paid in cash but with checks. On their way from the sperm bank, the duo happen across a crying girl called Katie, who is sitting on the street after a bad break up with her boyfriend has left her homeless. Leonard invites her to the restaurant, to Sheldon's dismay. When Sheldon can't figure out a good excuse, Leonard invites her to move into their apartment.Whilst Katie is showering, a nerdy friend of Sheldon and Leonard called Gilda shows up at the apartment. Gilda, who is shown to have the hots for Leonard who fantasizes about marrying him and having kids, feels threatened by Katie's presence but relaxes after Katie says she's not interested. Katie goes out drinking and arrives back at their apartment late at night, waking Leonard by smashing a lamp. Katie starts ranting to Leonard about her life and why it sucks, using the whiteboard, drawing colorful diagrams to explain her point. Leonard upsets her by suggesting her problems weren't caused by her mother, boyfriend etc., but by her making stupid decisions. As a result, she moves out. Katie comes back at the end of the episode explaining that staying there is her only rent-free choice. She takes Leonard, Sheldon and Gilda out dancing and they show their awkward dance moves.
Sheldon: Ghost on roller skates?
Leonard: I'm starting to think it's a penis.
Katie: They don't get out much.
While retaining portions of the pilot's plot, jokes, settings and characters, the Unaired Pilot has several key differences from the Broadcast Pilot, they include:
- The opening segment is much different than the Broadcast Pilot. It features a different song and a different opening.
- The characters Penny, Howard and Rajesh have not been created yet. Penny's precursor is Katie who has a different personality from Penny.
- The opening scene at the sperm bank plays out largely as it did in the Pilot, with two significant differences: Leonard and Sheldon are already at the sperm bank, instead of just walking in. Secondly, instead of changing their mind and leaving, Sheldon has already filled his sperm cup, and is paid (after threatening to take back the cup of sperm upon being told he'll be paid by check, rather than cash).
- Leonard and Sheldon have a geeky friend, colleague and love interest Gilda. As a female nerd with an interest in Leonard, she does appear to be a primitive Leslie Winkle-type character, although a bit different.
- Leonard and Sheldon dress in a different fashion which is more old-fashioned, rather than youthful, and Leonard wears dark suits.
- Sheldon is not asexual as he had slept with Gilda and has a fetish for women with large hind quarters (butts). He has also seen seven women naked, some of whom aren't even relatives.
- Sheldon doesn't have a spot in his home rather a table at the Bombay Palace.
- Sheldon is much more different than his series counterpart: he is sexually active, he frequently masturbates (as opposed to his counterpart asexual Sheldon) and has multiple fetishes, likes dancing and is more social than his counterpart. However, some parts of him were carried to the original Pilot.
- Sheldon likes to dance as opposed to his later counterpart. (This change stood out especially in season 3's "The Gothowitz Deviation" and result in him not dancing until season 4's "The Agreement Dissection")
- The set of the apartment is different and there is no broken elevator or indication that the apartment building has an elevator. The lighting in the apartment is also dimmer.
- The episode has a much more darker appearance (Leonard wearing dark suits, the song theme being filmed in the 90's), the apartment being darker, from which a negative result was made since the episode made the show in 90's themes.
- Katie's mocking and mean streak carried over to the regular series when Penny gets real mad.
- Katie (Amanda Walsh) was cut from the series due to an audience survey. She was criticized for being too mean towards Leonard and Sheldon.
- Positive reviews came in about the two guys (Leonard and Sheldon), so Chuck Lorre decided to add two more guys (Howard and Rajesh) into the mix.
- This episode makes numerous references to a sexually active Sheldon, as opposed to the largely asexual Sheldon of later episodes: Most notably Gilda and Sheldon admit to having previously had sex at a Star Trek convention (Howard doing something similar was revealed in season 5's "The Stag Convergence" as well as Sheldon mentioning pon farr, just before meeting Amy for the first time). Sheldon also apparently has a fetish for women with large butts, and brings a magazine of such women to the sperm bank for arousal.
- Katie works at a beauty salon. However, when the character is changed into Penny, she is a waitress at The Cheesecake Factory.
- Surprisingly, the only character other than Sheldon and Leonard to appear in the Broadcast Pilot is Althea, the nurse at the sperm bank. Her character has made several guest appearances on the show since. Her hair is different here than it was in the aired pilot.
- Sheldon's stated reason for his preferred table at the restaurant would later be adapted for the reasons for his spot.
- Leonard wielding his light saber upon hearing a noise late at night and Sheldon's difficulty of spotting sarcasm (minus Leonard's acknowledgement of this flaw, regarding Sheldon's high intellect) would later be used in "The Big Bran Hypothesis".
- Since the pilot was had a negative reaction, the show was almost cancelled from the start.
To be entered.