Continuity mistake: In "The Luminous Fish Effect" (S1E04) Sheldon tells Penny he weighs 140 pounds. In "The Porkchop Indeterminacy" (S1E16), he tells his sister he weighs 165. 25lbs difference would be a noticeable change, but he looks the same.
Suggested correction: Lying to Penny but not to his sister, not inconsistent with the characters and his relationships.
Visible crew/equipment: When Leonard, Sheldon and Penny are eating lunch for the first time, Penny sits on Sheldon's spot, Leonard then tells him to "Just sit somewhere else." He then walks over to his desk chair and contemplates sitting there and in the bottom left of the shot there is a chair with 4 false legs, and one large leg running down the middle. (00:08:20)
The Big Bran Hypothesis - S1-E2
Visible crew/equipment: At the very start, Raj walks over to his seat and a tape marker is visible on the floor. (00:00:05)