The One With Ross's Inappropriate Song - S9-E7
Continuity mistake: When the veal is served, Phoebe looks at her plate twice. (00:16:55)
The One With Ross's Inappropriate Song - S9-E7
Continuity mistake: When Ross is holding Emma, the position he is holding her changes.
The One With Ross's Inappropriate Song - S9-E7
Continuity mistake: When Chandler turns around and Joey watches the football game, the door to Chandler and Monica's room is open. However, when Joey sees the sex part of the tape in the next shot, as Chandler is about to turn around and the TV screen is visible, the door is shut. (00:14:29)
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.