Corrected entry: Leonard wonders aloud "I wonder who's going to tell his (Sheldon's) parents they're not having grandchildren." Leonard and Sheldon have been sharing the apartment for long enough for Leonard to know that Sheldon's father has been dead for a number of years, but it is at least since S1E04, when Sheldon's mother says "God rest his soul" while talking about his father.
Corrected entry: Stephen Hawking tells Sheldon he made an arithmetic mistake on page 2 of his paper. Sheldon then quickly turns pages on his paper to find the error, but Sheldon turns several pages of his paper, way past the second page, and still finds the error Stephen had noted.
Corrected entry: At the end of this episode when Penny asks to use Leonard and Sheldon's bathroom for a shower, when she goes down the hallway towards the bathroom/bedrooms, she turns past the bathroom (the door that is visible from the living room) and turns right and goes towards the bedrooms.
Corrected entry: Bernadette tells Howard that she chose the premature ejaculation project because neither of them has any heart diseases. However Howard has stated more than once that he has transient idiopathic arrhythmia. Also in the previous episode he actually emphasizes that his family has a history of heart diseases and alludes to a cave painting showing one of his ancestors clutching their chest.
Corrected entry: At the end of the episode, when Sheldon imagines going to the Grand Canyon to scream about Leonard, that's not the Grand Canyon, signs not withstanding. The location is Dead Horse Point State Park in Utah (near the town of Moab), with the view looking roughly south into Canyonlands National Park. [GPS near 38°28'12" by 109°44'30".] It's several hundred miles upriver from the Grand Canyon. [At least it is along the Colorado River.] The first national park sign looks authentic, but the small one at the overlook is fake, since that's not the Grand Canyon. And by the way, since it's just after New Year's, there would likely be snow at both the Grand Canyon and Dead Horse Point; the images used are not winter scenes.
Corrected entry: At the beginning, when Leonard has won the online auction, we see a shot of his laptop computer screen showing an Apple Safari browser window with Mac OS X window controls, but the laptop is a PC, not made by Apple. Mac OS X can only run on Mac hardware.
Corrected entry: Leonard and Sheldon live in 4A and Penny in 4B. Yet when they go to the mailbox downstairs, Sheldon's mailbox is the upper left one while Penny's is the third or fourth one from the left. Mail boxes have to be in apartment order, not necessarily for the tenant who could remember where their box is but for the mailman to be able to use the apartment number as to placement of the mailbox. Whenever a sub carrier would do the route, he wouldn't be able to follow the random pattern.
Corrected entry: In 3-14 "The Einstein Approximation" Bernadette stated that she is able to easily handle children as her Mother ran an illegal day care centre in their basement. However, in this episode she states that she hates children because her mother worked and she had to bring up her siblings, and she cannot properly react to children. So which is it? Can't be both.
Corrected entry: In 'Pilot' (season 1, episode 1), Leonard and Sheldon attempt to sell their sperm for money to install a T1 line in their apartment, and in 'The Dumpling Paradox' (season 1, episode 7), Sheldon says to Leonard "Frankly, if I could afford the rent, I would ask you to leave". Yet in this episode he says to Penny, "My expenses account for 46.9% of my after-tax income". The only way that his expenses could account for less than half his income just over a year after these lines can only really be explained away if the university gave him a pay rise of over 100%, which is incredibly unlikely for many reasons.
Corrected entry: In "The Loobenfield Decay" Sheldon and Leonard go to absurd lengths to avoid having to hear Penny perform because her singing voice is so horrible. But in series 2 episode 18 "The Work Song Nanocluster", series 3 episode 3 "The Gothowitz Deviation" and series 3 episode 8 "The Adhesive Duck Deficiency" (amongst others) she is shown to have a strong, pleasant singing voice, and she sings in front of both men without them objecting. They aren't just being polite - they genuinely like her singing. So, which is it?
Corrected entry: When Penny and Sheldon are driving to the supermarket, Sheldon is explaining the weight of the car and how it affects her braking time. He estimates the car's weight to be 4000 pounds, 140 for himself and 120 for Penny, and then rounds the total up to be 4400 pounds, when it actually should be 4260. It's extremely out of character for somebody like Sheldon to make such a basic addition mistake.
Corrected entry: Sheldon asks at the book store information desk if they have any books about making friends, and the employee tells him that all their books like that are for "little kids." It is unreasonable that the employee would not have been able to tell Sheldon about the very well known self-help book "How to Win Friends and Influence People," if Sheldon had not already been able to discover it through a cursory internet search.
Corrected entry: When Leonard is explaining his thoughts to Sheldon, during the rant which includes him naming who he intends with the words she or her (eg "She: Penny, Her: Leslie), he states, "Indicating that She: Penny had no interest in me asking Her: Penny out," which makes no sense. (00:03:40)