The One With The Free Porn - S4-E17
Visible crew/equipment: After Emily says thank you to Ross and leaves, when it cuts to Chandler and Joey's apartment Rachel puts a tea bag in her mug, and in the wideshot as she says, "He told me," the camera can be seen at the left side of the screen.
The One With The Free Porn - S4-E17
Visible crew/equipment: After Joey asks Ross to buy him a Toblerone just as Ross heads out to the airport, when it cuts to the shot of Rachel and Phoebe walking into the apartment, the camera can be seen at the right side of the screen.
The One With The Free Porn - S4-E17
Continuity mistake: Near the end, when Emily walks into the house, the TV should be on with the porn. But instead, it's turned off.
The One With The Free Porn - S4-E17
Continuity mistake: When Joey is asking Ross why he told Emily that he loves her, Joey's bottle of juice is right in front of him. In the next shot of Joey, there's two bottles - Monica's Diet Snapple and Joey's juice, and in the next shot it's back to one again. Monica's drink appears and disappears throughout the scene. (00:11:25)
The One With The Free Porn - S4-E17
Other mistake: 10:50pm boarding and departure, but it is broad daylight outside. (00:09:25)
The One With The Free Porn - S4-E17
Continuity mistake: In the scene where Phoebe tells the gang about her "Relaxitaxi" idea the position of Chandler's left arm changes between shots. In the frontal shots it's lying the back of the chair and in the shots from behind it's wrapped around Monica's shoulder.
The One With The Free Porn - S4-E17
Continuity mistake: In the beginning when Rachel says "Do we really have to watch this while we eat." From the front view Rachel's arms are crossed and then from the back their are by her side and back with no time to turn.
The One With The Free Porn - S4-E17
Factual error: We know that Phoebe is three months pregnant, because it's the day after the party where she told Joey that she was three months along. But the ultrasound shows three little lumps that in no way resemble a three-month fetus. An actual three-month fetus is the size of a jellybean.
The One With The Free Porn - S4-E17
Other mistake: The new York to London time sequence makes no sense. The friends are all wearing the same clothes throughout most of the episode. Emily flies from London back to New York and Ross flies to London, most trans Atlantic flights are overnight. It's very unrealistic that Ross got to London in the same day, and she flew back so quickly after getting back to London' even though Ross had only just said goodbye to her. The characters' clothes show this is all taking place in the same day.
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.