The One Where Joey Tells Rachel - S8-E16
Continuity mistake: When Monica and Chandler get back to the apartment Chandler tosses his coat over the back of the sofa, and while they're talking about soulmates and a house of cheese we can see Chandler's coat in the reflection on the TV, but then it vanishes in the reflection, though it reappears when Chandler says that he wants to take Monica out to a restaurant.
The One With The Tea Leaves - S8-E17
Continuity mistake: Throughout the entire first scene where Rachel is asking Chandler and Monica if they have seen Joey and he's in the bathroom, Chandler is sitting at the table and his blue cup constantly switches from being in his hand to on the table much too quickly to be real movement. At one point he even holds a piece of food which then disappears from his hand back on to the plate. (00:00:45)
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 Tea Leaves - S8-E17
Continuity mistake: When Ross opens Mona's door with the hidden key he only has to unsnap the door. Also, when Mona enters her flat a moment later she has to unlock the door. (00:10:50)
The One With The Tea Leaves - S8-E17
Continuity mistake: When Joey is picking up his bagel off the ground in Chandler's apartment he says something about the bagel hole being to small and he has it in his left hand. In the next shot it shows Chandler making a face and Joey's hand is empty. In the next shot Joey is sitting down and the bagel is back in his hand.
The One In Massapequa - S8-E18
Continuity mistake: When Monica shows Chandler the photo of Chi-Chi, as she says, "It's good stuff, huh," in the closeup Monica takes hold of the photo with her raised empty right hand, but in the next wide shot Monica is holding a Sharpie in her right hand and the photo is in her raised left hand. (00:02:25)
The One In Massapequa - S8-E18
Continuity mistake: In The One In Massapequa, Jack Gellar is eating food off a stick. When he finishes he holds the stick while Rachel asks Jack if he has any pearls of wisdom. We can see the stick over Judy's shoulder. In the next shot the stick is gone from his hand, then we see Judy put it down on a table, then it reappears in his hand, before disappearing for good. (00:05:05)
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 Joey's Interview - S8-E19
Continuity mistake: In the opening scene, Joey is holding the Soap Opera Digest magazine. In one shot it is open but folded, then in another it is open all the way, then it's folded again, then it's open again, then it's closed, and then it's folded again. The change is never shown.
The One With The Baby Shower - S8-E20
Continuity mistake: In the one with Rachel's babyshower, Monica needs to ring Rachel's mom to invite her. She says that she has her number in her phone book and walks over to the phone - we see her start to look at it, but when the angle changes she's got the phone and is dialling. (00:01:00)
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 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)
The One Where Rachel is Late - S8-E22
Continuity mistake: The first time Phoebe and Monica are making bets on when Rachel will give birth, Phoebe has a bottle of water in her hand and is holding it near her stomach. She puts it to her mouth to drink some, but in the next shot, the bottle is near her stomach again. (00:07:00)
The One Where Rachel is Late - S8-E22
Continuity mistake: In one scene, Rachel is using the bathroom. She yells out to Monica and Phoebe "Whose turn is it to help me get up?" A few scenes later Rachel goes to the bathroom again, but gets up with no one helping her. (00:07:05)
The One Where Rachel is Late - S8-E22
Continuity mistake: At the end, when Rachel and Ross leave for the hospital, Rachel grabs the keys. In the close-up, when Rachel asks, "Do you think we have time?" she holds the keys up in her left hand while Ross holds her empty right hand. It then cuts to a medium shot, and the keys are now in Rachel's right hand, the same hand Ross holds. (00:20:40)
The One Where Rachel Has a Baby, part 1 - S8-E23
Continuity mistake: At the beginning, when Rachel first arrives at the hospital, she is talking about the hospital not being out of rooms. She points to herself with her right hand saying 'What if I was the president?' Then when the shot changes to include Ross she is pointing to herself with her left hand, then it cuts back to just Rachel and she is using her right hand again. (00:01:25)
The One Where Rachel Has a Baby, part 1 - S8-E23
Continuity mistake: When the couple who has bad pet names for each other is sharing the maternity room with Rachel, the man is unpacking a suitcase that he closes, but in the next shot its open and he flips the top closed again. (00:09:10)
The One Where Rachel Has a Baby, part 2 - S8-E24
Continuity mistake: When Ross is telling Chandler that Janice is there and she's contracting Chandler can be seen putting his hands on his face. In the very next shot his hands are by his side again. (00:02:50)
The One Where Rachel Has a Baby, part 2 - S8-E24
Continuity mistake: While Rachel is having her baby she grabs Ross by the shirt and says 'you do it for me' in the next shot her hand is no-where near Ross. She couldn't have put her arm down that quickly. (00:33:50)
The One Where Rachel Has a Baby, part 2 - S8-E24
Continuity mistake: When Phoebe and Ross are standing in front of the screen looking at all the babies and talking about why He and Rachel aren't together, some of Phoebe's hair is in front of her shoulder on the right hand side then the shot changes looking over Phoebe's shoulder at Ross. Then when you see Phoebe again her hair is behind her shoulder yet she has not moved or touched her hair. (00:45:00)
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.