The Grasshopper Experiment - S1-E8
Continuity mistake: When Raj's parents tell him to put his laptop down and gather his friends, they all huddle around the one-seat sofa. Sheldon is crouched to the left of the seat with his hands on the sidearm, yet in shots angled at the left he has disappeared from his place (as to not obstruct these particular angled shots.) (00:02:00)
The Grasshopper Experiment - S1-E8
Deliberate mistake: At the end, Penny holds up a bottle of rum to show Leonard that she added it to his drink. However, the B is missing from the name "Bacardi" (00:19:30)
The Grasshopper Experiment - S1-E8
Continuity mistake: When Raj is drinking with Lalita in the bar Penny works at, in one shot he raises his Grasshopper drink to his lips with his left hand. In the next shot it's in his right (this is just before he says "Oh my God, you've lost so much weight").
The Grasshopper Experiment - S1-E8
Continuity mistake: When Raj starts talking to Penny after he drinks the Grasshopper drink in her apartment, in one frontal shot he lifts the drink and begins to drink but in the next shot from behind the drink is back on the counter.
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