The One With Monica's Thunder - S7-E1
Continuity mistake: Chandler is in Rachel's apartment after he has just left Monica; he says to Rachel, "You look great", then Rachel puts her hair behind her ears. The camera cuts to Chandler, then straight back to Rachel, and her hair is not behind her ears. (00:05:05)
The One With Monica's Thunder - S7-E1
Continuity mistake: In the scene where Phoebe is telling Joey that his eyes "give him away" he is holding a sandwich; the camera angle cuts to behind him and the sandwich is on the table. (00:15:50)
The One With The Truth About London - S7-E16
Continuity mistake: In the opening credits, Monica and Chandler are talking about which minister to use. Chandler's feet are crossed and on the table; at first his left leg is over his right, then in another shot his right leg is over his left. (00:02:45)
The One With The Truth About London - S7-E16
Continuity mistake: After Rachel shows Ben the pencil and quarter prank, she lays the pencil down and it is pointing straight ahead. When the pencil is shown again it has moved. (00:05:45)
The One With Monica and Chandler's Wedding, Part 1 - S7-E23
Continuity mistake: When Monica is talking to Chandler about nothing having gone wrong, Chandler's arms are crossed. The camera cuts, and his arms are down by his side. (00:06:50)
The One With The Engagement Picture - S7-E5
Continuity mistake: When 'Hums While He Pees' hands Phoebe the tickets for the ballroom dancing, they switch hands depending on the camera angle. She takes them in her right hand, but in the shot from behind she has them in her left hand. (00:08:25)
The One With The Truth About London - S7-E16
Continuity mistake: When Rachel goes to Carol's house and tries to tell Ben to stop playing pranks, her bag changes from being on her shoulder to in her hand in almost every shot. (00:12:25)
The One With Monica's Thunder - S7-E1
Continuity mistake: When Monica says "I nearly made you sleep with Ross" her hands are outstretched. The camera cuts and now they are instantly by her side. (00:21:05)
The One With The Vows - S7-E21
Continuity mistake: After Monica says "Oooh can we lie in our vows?" it cuts to Rachel then back to Monica leaning on her hands, but when it goes for a close up she is holding the pen in her right hand, there isn't enough time for her to naturally pick it up. (00:03:10)
The One With the Holiday Armadillo - S7-E10
Continuity mistake: When Ross is on the couch telling Ben about Chanukah, Ben's hair varies from shot to shot. In the first shot it's flat and in the next shot it's spiked up at the front. His hair stays spiked up for a few shots and then returns to flat. (00:06:00)
The One With Rachel's Big Kiss - S7-E20
Continuity mistake: When Melissa and Rachel are first reunited at the Central Perk, the way they hold their arms (crossed, hands on hips, etc.) changes with almost every shot. (00:00:45)
The One With Joey's New Brain - S7-E15
Continuity mistake: When Chandler, Ross and Monica are in Central Perk discussing playing bagpipes, and Ross says, "Decide whatever you want," he is gesturing with his right hand up and with an open book in his left hand. When the camera angle changes, the book is closed and is now in his right hand. (00:15:30)
The One With Monica and Chandler's Wedding, Part 1 - S7-E23
Continuity mistake: At the rehearsal dinner when Chandler loosens his tie and unbuttons his collar, the tie changes its appearance in the following shots from being tighter to looser several times. (00:09:30)
The One With Monica and Chandler's Wedding, Part 2 - S7-E24
Continuity mistake: As Chandler meets Monica at the altar, Monica's hand switches from holding Chandler's hand, to holding the flowers, with no time to do so. (00:40:40)
The One With the Holiday Armadillo - S7-E10
Continuity mistake: In the scene where Ross takes a liquorice from the skull, in the first close up shot he is holding it in his hand, but then immediately after this when they zoom out, he is chewing a piece. This is impossible because he would have had no time to bite it. (00:00:50)
The One With Monica and Chandler's Wedding, Part 2 - S7-E24
Continuity mistake: The way Phoebe holds her flowers when told to smile changes depending on the angle. (00:04:30)
The One With Chandler's Dad - S7-E22
Continuity mistake: When Monica and Chandler are in Las Vegas watching the burlesque show, Chandler turns the light on the middle of the table off to "hide" from his Dad. When Monica calls out saying "Waiter. Waitress.", the light is suddenly back on and remains on for the rest of the scene. (00:15:50)
The One Where They're Up All Night - S7-E12
Continuity mistake: There is a long shot of Rachel and another person sitting on the sofa and Rachel's wine glass is almost empty. She then goes over to the the counter to fill it up. However, before she starts to fill it, a significant quantity of wine can be seen in the glass. (00:07:35)
The One With The Truth About London - S7-E16
Continuity mistake: At the beginning when Chandler is talking about two reasons to pick a minister, he counts them using his left hand. However, in the wide shot straight afterward his right hand has two fingers up and his left hand is in his lap. (00:02:00)
The One Where They All Turn Thirty - S7-E14
Continuity mistake: In one of Monica's flashbacks, her hands move between shots with no time to do so. (00:10:50)
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.