The Maternal Capacitance - S2-E15
Continuity mistake: After Leonard's mother says, 'Tell me about it', her head was tilted downwards, but in the next shot, she was looking straight again. (00:04:35)
The Maternal Capacitance - S2-E15
Character mistake: Leonard has his phone on his left ear. Sheldon says "Since ears don't cross hemispheres..." This is an error. The vast majority of the input to the left (or right) ear crosses over to the opposite hemisphere.
The Cushion Saturation - S2-E16
Factual error: Leslie Winkle takes shelter with Howard in the middle of a paintball game. Her gun has no hopper for paintballs and thus no ammo, so it's useless, despite her apparently using it outside seconds earlier. This isn't a model with an internal magazine - the port to attach the missing hopper is plainly visible.
The Cushion Saturation - S2-E16
Continuity mistake: When Howard and Leslie are in the paintball shed, Howard's paintball ammo pack is closed, but when he and Leslie start kissing, it's open.
The Work Song Nanocluster - S2-E18
Continuity mistake: When Penny puts the box down at the start it is closed. Camera cuts and it's open instantly.
The Work Song Nanocluster - S2-E18
Continuity mistake: When Penny gets the package, the position of the box on the counter keeps changing position.
The Dead Hooker Juxtaposition - S2-E19
Continuity mistake: In the scene after the boys have followed the new neighbor out and Sheldon and Penny are left eating alone, the utensils Penny holds change from chopsticks to a plastic fork and back several times.
The Dead Hooker Juxtaposition - S2-E19
Continuity mistake: After the guys leave and Penny and Sheldon are eating alone, Sheldon's chopsticks switch between an unevenly broken pair of chopsticks and an evenly broken pair of chopsticks.
The Hofstadter Isotope - S2-E20
Continuity mistake: Near the end of a conversation with Stewart, Penny is holding a drawing that Stewart drew for her. In the next shot, it is now on the counter and she is picking it up.
The Vegas Renormalization - S2-E21
Continuity mistake: When Leonard and Raj are getting ready in the bathroom, Raj picks up a tube of shampoo/conditioner off the bathroom bench with his left hand. However, in the next shot, Raj has nothing in his left hand and the tube is back on the bench, with no time for him to replace it between shots.
The Vegas Renormalization - S2-E21
Continuity mistake: In the bathroom of the hotel in Las Vegas, we can see Rajesh taking a small white bottle and keeping it in his hand while saying "I love Las Vegas". In the next shot, the bottle has returned to its place instantly.
The Classified Materials Turbulence - S2-E22
Continuity mistake: In the comic book store, when Stuart and Leonard are talking about Penny saying "Leonard" when with Stuart, Stuart's pen/hand is constantly changing position instantly.
The Classified Materials Turbulence - S2-E22
Continuity mistake: When Raj is going through the ideas on what would work to fix the toilet, Sheldon's hand is not near his face, but when Howard talks about moving to Israel, Sheldon's hand is up by his face.
The Classified Materials Turbulence - S2-E22
Continuity mistake: Leonard is talking to Stuart at the door to his (Leonard's) apartment. Howard then comes over and slams the door in Stuart's face and Leonard has moved back about 4-ft instantly.
The Monopolar Expedition - S2-E23
Continuity mistake: When Penny finds out about the expedition, Sheldon starts to walk to his apartment. Camera cuts to Leonard in the apartment for five seconds and then to Penny in the doorway. Behind her, you can see Sheldon walking to the apartment still. Since he was halfway to start with, he should be in the apartment by now. (00:10:35)
Chosen answer: The song is called "Dark as a Dungeon" and was written and first performed by singer-songwriter Merle Travis in 1946. It has been performed by a wide array of artists, including Tennessee Ernie Ford, Harry Belafonte, Dolly Parton, Queens of the Stone Age, Kathy Mattea and Amy Grant. But it was made most famous when it was performed and recorded by Johnny Cash during his concert at Folsom Prison in 1968. According to Wikipedia: "It is a lament about the danger and drudgery of being a coal miner in an Appalachian shaft mine. It has become a rallying song among miners seeking improved working conditions."
Michael Albert