The One With The Video Tape - S8-E4
Continuity mistake: When Ross turns on the camera and sits down in front of it, "flirting" with it and drinking wine, what you can see on the little camera screen is very different from when they play the same clip on the TV, in which looks like he was sitting much closer to the camera then he actually was.
The One With The Video Tape - S8-E4
Continuity mistake: When Ross walks into Joey's apartment after everyone watched the tape, you see him come in and they cut to Rachel and you hear a door close, they cut back to Ross and the door is still open and he shuts it again. (00:20:00)
The One With The Video Tape - S8-E4
Continuity mistake: When we see the video, notice Rachel's hair. It is the same length as it is throughout season 8, but her hair is supposed to be the short bob she had in season 7 since it took place then. (00:17:00)
The One With The Video Tape - S8-E4
Continuity mistake: When Rachel has the tape and is explaining why she wants to watch it, she is holding it in her left hand with her right hand on her chest, when the shot changes to behind her, she has it in her right hand. (00:15:30)
The One With The Video Tape - S8-E4
Continuity mistake: As Joey says thanks to Ross for his offer to help him if he has a problem with the ladies, he puts his hand on Ross's arm. Camera cuts and it is by his side with no time to move it. (00:11:35)
The One With The Video Tape - S8-E4
Continuity mistake: When Chandler and Monica are trying to call Greg and Jennie, the water bottles on the table move around. Phoebe and Joey didn't move them, they are drinking from the cans. (00:05:30)
The One With The Video Tape - S8-E4
Continuity mistake: As Rachel goes to put the video on, Ross hangs his head. The camera cuts and now it isn't hanging. There was no time to move it between camera cut. (00:16:10)
The One With The Video Tape - S8-E4
Continuity mistake: When Chandler says about Ross and Rachel having a baby, He lifts his bottle to have a drink, camera changes and he raises it again. (00:02:25)
The One With The Video Tape - S8-E4
Continuity mistake: As Rachel says, "Let's be honest" to Ross, her hands are in her lap. The camera cuts and now she is gesturing with them. (00:03:30)
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 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)
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.