The One After Joey And Rachel Kiss - S10-E1
Visible crew/equipment: After the gang leaves Rachel's room, right after she asks Joey "Are they right?", if you look above Joey's head, for a split of a second you will see a boom mic. (00:09:25)
The One With Ross's Grant - S10-E6
Visible crew/equipment: When Dr.Hobart enters the meeting room to conduct the grant interviews, markers can be seen on the floor around the first chair's wheels as well as in front of the table. (00:12:25)
The One Where The Stripper Cries - S10-E11
Visible crew/equipment: In the scene with the conversation with the stripper, there is a large vase on the kitchen table. Several lights, the top of the stage and a few crew members are reflected in it.
The One With Princess Consuela - S10-E14
Visible crew/equipment: When Ross enters Central Perk with champagne, straight away when he walks over to the sofa, look above the door. In the reflection of the top window, you can see several stage lights. (00:08:45)
The One With Ross's Tan - S10-E3
Visible crew/equipment: When Rachel is talking to Monica about how weird the thing with Joey was, behind her in a yellow vase, you can see a huge light blur reflected from a stage light. (00:12:50)
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.