The One With Ross's Library Book - S7-E7
Continuity mistake: At the very beginning, Joey is eating some cereal and then says he has to go to work, so puts it down on the table - but in the rest of the scene it vanishes. (00:00:15)
The One With Ross's Library Book - S7-E7
Continuity mistake: When Janice sees Monica's ring, she's wiping her hands with a rag, then it disappears. (00:03:50)
The One With Ross's Library Book - S7-E7
Continuity mistake: When Chandler says "lie" his hand is by his side, then up. (00:07:20)
The One With Ross's Library Book - S7-E7
Continuity mistake: When Monica says, "she's not going to like that chicken either," Chandler's arms are crossed. Then the shot changes, and they're now by his face. (00:07:50)
The One With Ross's Library Book - S7-E7
Continuity mistake: When Monica says, "She has beaten me, Chandler, I'm tired," she puts her hands on him and they are in fists, then they are flat out, then in fists again.
The One With Ross's Library Book - S7-E7
Continuity mistake: When Phoebe is eating the muffin, it has no white paste on it. Then the shot changes and there's a line of white paste.
The One With Ross's Library Book - S7-E7
Continuity mistake: After Monica tells Chandler that they are going to have lunch with Janice, it shows Central Perk. The people in the window are different when the shot changes.
The One With Ross's Library Book - S7-E7
Continuity mistake: When Rachel asks Ross what's wrong, her hand is up. Shot changes and it's down.
The One Where Chandler Doesn't Like Dogs - S7-E8
Continuity mistake: In this episode, it is stated that Ross does not like ice cream because it's too cold. However, back in The One Where Ross Dates a Student, you can see Ross on a date with Elizabeth eating an ice cream.
The One Where Chandler Doesn't Like Dogs - S7-E8
Continuity mistake: When Rachel and Tag are on the balcony and Tag says, "What did Joey say? I like you back?" he is standing on the balcony with one hand in his pocket and the other in front of him. As the camera angle changes, Tag is now in a different position, with both his hands behind him, leaning against the balcony before he moves forward.
The One Where Chandler Doesn't Like Dogs - S7-E8
Continuity mistake: When Chandler is looking over Ross' list (right before he calls him Magellan), he has the front sheet of the paper folded up. In the next shot, the sheet is folded down.
The One With All The Candy - S7-E9
Continuity mistake: When Phoebe tries to show the gang she can ride her bike, the large metal bike rack at the curb changes position between shots. (00:09:50)
The One With All The Candy - S7-E9
Continuity mistake: When Phoebe sits on the swing (when learning to ride her bike), her scarf has one end down her front and the other over her left shoulder. In the next shot, the end is over her right shoulder instead of her left. A couple of shots later, it is switched back again. (00:11:05)
The One With All The Candy - S7-E9
Continuity mistake: When Ross is trying to convince Phoebe to try to learn to ride her bike again, the bike is completely covered by a large white sheet in the corner of Phoebe's room; however, in a later shot, the wheel of the bike is visible. (00:13:15)
The One With All The Candy - S7-E9
Continuity mistake: In the scene where Monica's female neighbour comes begging for candy, after Monica gives it to her and shuts the door it's a man standing at the door not the neighbour.
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 the Holiday Armadillo - S7-E10
Continuity mistake: During this episode, Chandler is having major problems slipping people dollar bills. He asks Monica if Richard (her ex) use to slip people notes. But in Series 2 there was an episode where Chandler and Joey were doing impressions of Richard; they impersonate him by slipping money to each other with no problems. So not only has Chandler forgotten that Richard used to slip money, he's also lost the ability to slip money himself. (00:05:05)
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 All The Cheesecakes - S7-E11
Continuity mistake: Phoebe and David see each other at the coffee house and start talking. The buttons on Phoebe's red cardigan go from gaping to properly shut a number of times throughout the scene. (00:09:30)
The One With All The Cheesecakes - S7-E11
Continuity mistake: When Ross and Monica are at the wedding reception talking to the other guests at their table, a lady wearing a red scarf is standing behind them with her back turned. Throughout the scene the red scarf keeps changing position very quickly - in one shot it's slid down one shoulder, then back up in the next and then slid down again. At the end of the scene it's off her back entirely and she has just slung it over her arms. (00:12:15 - 00:13:15)
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.