Laryngitis - S1-E18
Continuity mistake: During the "Lady is a Tramp" number, Puck puts on a hat with the front of the brim flipped down. The brim miraculously flips up and back down throughout the scene.
Continuity mistake: In "Gives You Hell", while Rachel is sliding down the middle in the chair you can see Puck on the left then on the right. He couldn't move that fast in a second.
Continuity mistake: During the song express yourself, whilst the girls are dancing on the stage Quinn appears to have a flat stomach but she is supposed to be pregnant at this stage.
Continuity mistake: When Rachel and Ms. Corcoron sing "Poker Face", near the end they switch places between shots.
Answer: According to IMDb.com, Ian Brennan, one of the "Glee" writers and producers, is listed as the uncredited narrator voice.
Michael Albert