Other mistake: When Chandler says "We just got married. Right there!" and points. We hear a small 'ding' and Monica asks "Is that your ring?" But when Chandler pointed, you can see that all of his fingers except his index finger are closed to his hand. So the ring couldn't have come off. (00:00:05)
The One With The Stripper - S8-E8
Continuity mistake: When Ross and Mona are having their "make-up" kiss, Mona puts her left arm around Ross's neck, then in the next shot she does it again. (00:18:50)
The One With The Halloween Party - S8-E6
Continuity mistake: When Rachel returns from running after the boy that she told to "shut up", you see Joey picking up a piece of food, sniffing it and making a face and then putting it back on the tray. However in the next shot, without moving, Joey is munching on something - he didn't have anything in his hand before. (00:19:55)
The One With The Video Tape - S8-E4
Continuity mistake: At the end, Monica goes to dial a number, the camera changes and she has dialed with no time. (00:22:20)
The One Where Joey Dates Rachel - S8-E12
Factual error: The premise of Chandler filling the high score list with dirty words is not possible for this game. Ms. Pac-Man only keeps track of a single high score, which is always displayed at the top of the screen. Unlike many other games of the era, there is no screen showing a list of additional top scores alongside initials during the attract mode, and there is not even a mechanism for entering initials within the game's code.
The One With Monica's Boots - S8-E10
Visible crew/equipment: When Chandler is giving Monica a piggy-back, Monica sees her boots in tan in the store window. In the non-widescreen version, the cameraman can be seen in the reflection of the glass. This was fixed in the widescreen version. (00:17:45)
The One With Monica's Boots - S8-E10
Visible crew/equipment: When Joey is talking to Bobby and Dina, lights and a boom mike can be seen at the top of the screen. (00:18:40)
The One With The Halloween Party - S8-E6
Visible crew/equipment: Right after Joey has finished his impersonation of Chandler, kids can be heard knocking on the door. When the camera pans to Rachel, stage lights can be seen in the top right-hand side of the screen. (00:05:15)
The One With The Halloween Party - S8-E6
Continuity mistake: While Phoebe is calling out Ursula for lying to Eric, her hair continuously changes position from behind her shoulder to in front of her shoulder depending on the camera angle. (00:14:50)
The One Where Rachel is Late - S8-E22
Visible crew/equipment: After Rachel has told Ross it's 100° outside and she starts walking towards the door, a camera is visible to the far right (Widescreen version only). (00:09:30)
The One With The Baby Shower - S8-E20
Continuity mistake: During the mock Bamboozled game with Chandler and Ross, when Joey asks about the word triskaidekaphobia a bottle of Evian suddenly appears on the countertop oven, which vanishes and then reappears.
The One With Joey's Interview - S8-E19
Continuity mistake: In the opening scene Rachel is holding a white felt pen in her hands and gesturing with it while she talks about the soap opera digest magazine. Between shots the pen sometimes has its cap on and then it's off again so you can see the blue tip. (00:00:20)
The One With Rachel's Date - S8-E5
Visible crew/equipment: When Rachel and Cash leave Joey's apartment, in the top-left corner a stage light is visible. (00:12:05)
The One With The Birthing Video - S8-E15
Revealing mistake: When Monica gets out of her room to show Chandler her sexy clothing, as she opens the room's door, the buildings from across the street move. The scenario was a curtain and the wind that the door made when she opened it on the set made those curtains with the buildings printed in move. (00:06:25)
The One With Rachel's Date - S8-E5
Visible crew/equipment: When Phoebe is telling Monica about Tim, there is someone in the background with a black mug that is reflecting some of the stage lights. (00:05:20)
The One With The Video Tape - S8-E4
Continuity mistake: When Rachel is finding out that people know the Europe story, hers legs keep changing positions. (00:19:15)
The One With The Tea Leaves - S8-E17
Continuity mistake: When Pheobe is reading the tea leaves, Chandler lowers his cup. The camera cuts and he lowers his cup again. (00:04:30)
The One With The Halloween Party - S8-E6
Continuity mistake: When Chandler and Ross are arguing, the nose on Chandler's costume moves. In one shot it's on his chin. The camera then cuts to Joey and Monica and back, and then it's down round his neck. (00:12:20)
The One With Rachel's Date - S8-E5
Continuity mistake: At the end when Rachel comes into the coffee house and sees Mona with Ross, she is holding a brown paper bag. When you see her in the background, the the top of the paper bag is rolled over away from her. When the camera switches to just Rachel, the paper bag is the other way around with the top rolled over towards her. (00:21:35)
The One With The Cooking Class - S8-E21
Continuity mistake: The night before they go to the baby furniture store, Ross and Rachel are in the kitchen talking. Just before they leave the kitchen watch Rachel's robe: in one shot the 'lapels' are neatly one over the other, and in the next shot one lapel has moved lower and looks halfway folded over as if she hastily pulled the robe together. (00:03:15)
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.