The One Where No One Proposes - S9-E1
Continuity mistake: In the scene where Rachel believes Joey has proposed to her at the hospital after having Emma. Ross is talking to Rachel about her saying yes to Joey's proposal. The nurse brings Emma in to breast feed. When the nurse leaves, she closes the door. However, when they shoot back to Joey a couple of times before he leaves the room, the door is open. (00:19:45)
The One Where No One Proposes - S9-E1
Continuity mistake: In the one where Rachel is in the hospital after having Emma she is in the bed feeding Emma and Ross is sitting right beside of her. They are talking about their relationship and what should come. If you will watch each shot as they go to showing Rachel's face then Ross's you can see that Rachel's hair in one shot is in front of her shoulder and the next shot it is behind her shoulder. This happens several times. (00:20:55)
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.