The One Where No One's Ready - S3-E2
Continuity mistake: In the scene where Chandler sits on Joey in an attempt to regain possession of his seat, the shirt sleeve on his left arm becomes unrolled and slides down. When he stands up, the camera cuts to face Ross while he is giving out directions, leaving Chandler's back to the audience. Chandler's sleeve is now rolled back up. The sleeve remains rolled for the rest of the sequence. (00:06:30)
The One Where No One's Ready - S3-E2
Continuity mistake: When Joey refuses to give Chandler the chair, Phoebe gets hummus on her dress, but in some scenes the stain is much smaller than others. (00:07:00 - 00:08:00)
The One Where No One's Ready - S3-E2
Continuity mistake: The amount of fat in the glass differs throughout the length of the episode. (00:00:05 - 00:15:00)
The One Where No One's Ready - S3-E2
Other mistake: When Monica beeps into Richard's machine and changes the outgoing message, she always presses the same two buttons when trying to interact with his machine, but gets a different result each time. (00:19:00)
The One Where No One's Ready - S3-E2
Visible crew/equipment: When Ross tells Chandler and Joey, "I'd feel a whole lot better if you got dressed now," the reflections on the TV screen show there's a crew member at the side of the sofa wearing a white T-shirt, as well as the camera and camera operator behind the sofa. (00:00:30)
The One Where No One's Ready - S3-E2
Visible crew/equipment: After Rachel agrees that it will indeed take her 6 or 7 minutes to get dressed, with the caveat, "Once I figure out what I'm wearing," it cuts to Joey offering Ross the "glass of fat" as he stands behind the couch. In the next shot of Ross, the reflections on the TV screen show Joey is still sitting on the couch, and the camera and camera operator (wearing a dark shirt and raises an arm) behind the sofa. (00:01:15)
The One Where No One's Ready - S3-E2
Continuity mistake: When Ross asks Chandler "you took his underwear?", the angle changes halfway through the line. Chandler's hands go from in front of him to being in his pockets. (00:10:50)
The One Where No One's Ready - S3-E2
Continuity mistake: When Phoebe comes out of the bathroom after trying to get out the hummus stain on her dress, the bathroom door is left wide open. But when Monica is playing her message, the door is suddenly almost shut, though no-one had gone near the door.
The One Where No One's Ready - S3-E2
Continuity mistake: Just before Rachel and Ross are leaving Monica's apartment at the end, Rachel stops by the door but the next shot they're further in the room, then they walk past the door and out.
Answer: Usually by the seventh night of Hanukkah you don't know what to get the other person, and you will probably resort to getting the other person something insignificant. Chandler is basically saying that the pen is a stupid gift.