The Big Bang Theory (2007)

The Countdown Reflection - S5-E24

Factual error: There is not a snowball's chance of Howard becoming an astronaut. He suffers from cardiac arrhythmia, something about which he is completely open. "Transient" or not this is easily detectable by a simple electrocardiogram, which is a fundamental part of the many medical examinations a potential astronaut will have to pass. He wouldn't even be allowed to start basic training. Note also that during his basic training he shows signs of severe stress and trauma which would inevitably trigger a cardiac episode. Even if it didn't the fact that he was falling apart at the seams would have him removed from the programme for his own good.

The Staircase Implementation - S3-E22

Leonard: Oh, screw the roommate agreement!
Sheldon: No, you don't screw the roommate agreement! The roommate agreement screws you!

The Work Song Nanocluster - S2-E18

Trivia: After Sheldon mentions a molecular sieve, they go over to 4a, their apartment. 4a is a kind of molecular sieve.

The Euclid Alternative - S2-E5

Question: Though it comes up in other episodes as well, this one is focused on Sheldon needing a ride everywhere he goes because he can't drive, not to mention his not being welcome on the bus. Of course, this story element would be nonexistent if there was a simple answer, but it does beg the question: Does Pasadena not have taxicabs?

MFWills