A Stunted Childhood and a Can of Fancy Mixed Nuts - S2-E10
Continuity mistake: When Paige arrives for a sleepover, Mary closes the door, and her hand is by her waist. When the shot changes, her hand is now down against her leg. (00:04:10)
A Crisis of Faith and Octopus Aliens - S2-E3
Continuity mistake: Just after the opening titles, Mary is preparing a salad when the phone rings. Between the shot of Mary and Connie and the shot of just Mary, the position of the items in her hands changes rather drastically. (00:01:50)
German for Beginners and a Crazy Old Man with a Bat - S6-E20
Character mistake: Sheldon says that "entrez vous" is German for "come in." That is actually French.
Suggested correction: He says "eintreten."
Ants on a Log and a Cheating Winker - S7-E4
Other mistake: Sheldon (in the voice-over) says "it really brought what's his name and I closer together." The grammatically correct expression is "brought what's his name and ME closer together", and a stickler like Sheldon would not make that mistake.
A Sneeze, Detention, and Sissy Spacek - S1-E13
Continuity mistake: When the principal gets the paddle out of the drawer, he holds it in two hands. But as he goes to sit down, he is only holding it in one hand. (00:02:30)