The One With The Mugging - S9-E15
Visible crew/equipment: When Chandler slips while wearing the shoes, if you look above Monica and Rachel, you will see a stage light.
The One With The Lottery - S9-E18
Visible crew/equipment: At the start when they have the tickets and the empty bowl, you can see some of the stage lights in the bowl's reflection. (00:02:00)
The One With Rachel's Dream - S9-E19
Visible crew/equipment: After Monica and Phoebe apologize to each other at Javu, when it cuts to Rachel walking into the apartment we can see part of the hole in the wall beside the bulletin board, and the light fixture above it is gone.
The One With The Soap Opera Party - S9-E20
Visible crew/equipment: After Ross introduces Charlie to Phoebe and Monica in Monica's' apartment Charlies' cell phone rings. She turns around and in the back where the "secret closet" is, you can see on the left corner two spotlights.
The One With The Soap Opera Party - S9-E20
Visible crew/equipment: When the roof party begins, above the door a boom mic is visible.
The One With The Fertility Test - S9-E21
Visible crew/equipment: When Monica and Chandler are on the couch in the fertility clinic after Monica says "Nobody's gonna wanna watch that" the camera switches to a wider shot. When it does this the boom mic swiftly moves out of view. (00:12:20)
The One With The Fertility Test - S9-E21
Visible crew/equipment: When Chandler is given the cup at the clinic, a boom shadow can be seen on the wall. (00:12:50)
The One With The Fertility Test - S9-E21
Visible crew/equipment: After Chandler tells Monica the results of the fertility tests, when it cuts to Phoebe as the receptionist says good morning to her, the camera can be seen at the left side of the screen.
The One With The Donor - S9-E22
Visible crew/equipment: After Chandler explains to Monica why he brought Zack home, just as Chandler leans over the couch to hand Zack the bottle of beer, the camera and a crew member can be seen at the left side of the screen.
The One In Barbados, part 1 - S9-E23
Visible crew/equipment: After Monica and Phoebe leave, David and Chandler are still at Central Perk and when David comments that Phoebe is still hung up on Mike the camera can be seen at the right side of the screen.
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: Right before Ross' speech begins, as the camera pans down, if you look at the top of the screen, you would be able to see the top of the set and a set light. (00:31:20)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: When Mike and Monica are playing ping pong after Mike says "do you wanna volley a bit for serve?" when the camera switches to a wider shot the microphone dips into view above Monica's head. (00:32:00)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: When Ross and Charlie are hiding behind the the plant the camera switches to a wider shot of the the three scientists looking around.When it does this the microphone is very visible at the top of the screen. (00:45:00)
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: During Monica and Mike's game, after Mike makes the comment that Monica should look in the mirror before calling herself a girl, in the following wideshot after the closeups the camera/equipment can be seen at the right side of the screen.
The One In Barbados, part 2 - S9-E24
Visible crew/equipment: While Joey's wearing the snorkel gear he blows a grape out of his snorkel tube, and when Charlie walks into the room the opening in the wall can be seen beside the door.
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.