The One With The Stripper - S8-E8
Continuity mistake: When the stripper has just entered the apartment you can see her putting down her right arm twice, without enough time in between to put it back up. (00:09:50)
The One With Rachel's New Dress - S4-E18
Continuity mistake: When Monica tells Rachel what she is cooking, and Rachel says "I really get crabby when I cook" she crosses her arms and in a flash they are on the counter again. (00:06:00)
The One With The Hypnosis Tape - S3-E18
Visible crew/equipment: When Monica leaves the apartment and everyone is watching you can see the stage lights on the ceiling in shots from Pete's viewpoint. (00:18:10)
The One In Vegas, Part 2 - S5-E24
Continuity mistake: When Rachel is saying to Ross that the pen won't come off, a wheel behind Rachel is spinning or stopped dead in different shots. This includes instant cuts between the 2 angles. (00:12:35)
The One Where Eddie Won't Go - S2-E19
Continuity mistake: When Eddie leaves Chandler's room, you can see it's not the living area. (00:01:10)
The One With The Inappropriate Sister - S5-E10
Continuity mistake: Rachel goes into Danny's apartment and we see that his door opens up right into his living room. However, in "The One With The Yeti", we see Danny's apartment from outside the door and there is a wall directly behind him. (00:11:00)
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 With The Giant Poking Device - S3-E8
Continuity mistake: At the end when Chandler is singing "Endless Love", Phoebe comes in and when she walks over to Chandler he has his arms wrapped around the Lionel Richie record with the shoe in his hand in front of the record. When the shot switches to just Chandler, his right arm is resting on the arm of the chair and his left arm is holding the shoe behind the record. (00:21:00)
The One With The Screamer - S3-E22
Continuity mistake: After the play, Joey asks Kate how she is doing, and she says "fabulous". She brings a cup to her mouth, and then does it again from another direction. (00:09:30)
The One With The Ball - S5-E21
Continuity mistake: When Monica says "Let's go team Monica!" Joey is holding the ball; when the camera angle changes Chandler has the ball and throws it behind him for someone else to catch. (00:18:15)
The One With The Apothecary Table - S6-E11
Continuity mistake: In the previous episode, Monica's Christmas tree is up in her apartment. After the party, Joey kisses Janine. In the next episode, he walks into Monica's apartment and says he just kissed her. However, Monica's tree is down and they have all changed their clothes. Surely if he just kissed her then it is still the same night of the party, therefore the tree should be up and Monica, Ross and Joey should be wearing the same clothes from the party. (00:00:05)
The One In Barbados, part 2 - S9-E24
Continuity mistake: In the One in Barbados (part 2), just after Monica bashes her hand against the table, the shot of Chandler asking if she's OK shows Monica raising a finger right at the edge of the screen. We then cut to Monica, who's cradling both her hands together. (00:42:50)
The One After Ross Says Rachel - S5-E1
Revealing mistake: When Phoebe phones Emily's step-mother to say she is Ross' doctor, she looks out the window behind Phoebe. The buildings are moving slowly from side to side. (00:04:10)
The One With The Lottery - S9-E18
Continuity mistake: In The One With The Lottery, Chandler is on the phone to find out if he got the job, he then hangs up and rolls up one of his sleeves. In the next shot of him both sleeves are rolled up. Then you can see his sleeves slip down again, but when it cuts to a closer shot, you can see they're rolled up again. (00:04:40)
The One Where Estelle Dies - S10-E15
Continuity mistake: Near the end when Chandler is talking to Janice at one point his hands go from pointing straight ahead to his pockets. (00:17:20)
The One with the Blackout - S1-E7
Continuity mistake: In the scene where Joey is standing with candelight over Ross' neck, the candle is full length, but in the next shot it's only half length. (00:13:00)
Continuity mistake: In the scene just before Joey goes into the shower, when he is thanking the director for the opportunity, the camera shot goes back and forth between Joey and the director several times. During this series of shots, the part in Joey's hair switches sides nearly every time. It appears that the entire shot is reversed - in the closeup, the shower curtain is on his left and the shadow to his right is sharply focused. In the lower (long) shot, the curtain is to his right, and the shadow on his left is more focused. (00:13:05)
The One Where Chandler Doesn't Like Dogs - S7-E8
Deliberate mistake: Monica sees the dog on her settee from Ross's apartment, which wouldn't be possible from the angle as Ross's place is lower than Monica's. (00:04:50)
The One After the Superbowl, part 2 - S2-E13
Continuity mistake: In the coffee house, while Chandler is talking about his date with Susie, a tall man with a blue shirt and vest gets up and walks toward the door twice. (00:07:30)
The One Where Phoebe Hates PBS - S5-E4
Continuity mistake: Monica comes to get her pan back from Chandler, and when she opens the door, the magna doodle pen is hanging down. The shot changes and it is attached to the board; it changes again and it is hanging once more. (00:12:00)
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.