The Comic Book Store Regeneration - S8-E15
Continuity mistake: While in Penny's apartment, Sheldon is folding laundry and Penny is talking to him from the kitchen counter. Between shots, the water bottle in front of Penny moves by itself to different spots on the counter.
The Comic Book Store Regeneration - S8-E15
Continuity mistake: While Bernadette is talking with Howard about Stuart living in Mrs. Walowitz's home, she is taking items out of a grocery bag. One of the bags of food changes spots on the table in the next shot.
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