The One With The Embryos - S4-E12
Visible crew/equipment: When Rachel crosses the boys' apartment to see what is in the drawer, if you look up to the right, you can see a glimpse of a boom mic. (00:20:25)
The One With The Embryos - S4-E12
Visible crew/equipment: When Rachel is protesting that she loves her apartment, look very carefully towards the top of the screen on the long shot of Monica and Rachel before it zooms in and you will see the shadow of a microphone move swiftly across the wall. (00:17:40)
The One With The Embryos - S4-E12
Visible crew/equipment: In the shot where Monica suggests that Ross creates the questions, there is a red boom mic followed by a blue boom mic at the top center of the screen. (00:05:15)
The One With The Embryos - S4-E12
Visible crew/equipment: Near the beginning of the show when Joey asks them who's going to ask the questions a boom mic is visible over Monica's head. (00:05:05)
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.