The One With Ross's Grant - S10-E6
Visible crew/equipment: When Dr.Hobart enters the meeting room to conduct the grant interviews, markers can be seen on the floor around the first chair's wheels as well as in front of the table. (00:12:25)
The One Where Joey Speaks French - S10-E13
Other mistake: When Joey auditions near the end and Phoebe steps in to explain to the producer/audition guy, she speaks French and the subtitles say, 'He is a little bit retarted' instead of 'He is a little bit retarded.' (00:18:35)
The One With Princess Consuela - S10-E14
Visible crew/equipment: When Ross enters Central Perk with champagne, straight away when he walks over to the sofa, look above the door. In the reflection of the top window, you can see several stage lights. (00:08:45)
The One With Princess Consuela - S10-E14
Continuity mistake: When Phoebe and Mike are at Central Perk discussing their name changes, his scarf goes from being hung loose around his neck to tied around his neck from shot to shot. (00:12:15)
The One With The Cake - S10-E4
Continuity mistake: Just before Rachel and Ross come back from the cake store, Monica is holding Emma on her lap. Emma is holding a green toy in one shot, when the camera angle changes it is nowhere to be seen. (00:19:30)
The One With The Cake - S10-E4
Continuity mistake: At the end after Rachel and Ross have come back from the cake store, when they are asking Emma how old she is, we can see Joey walking to sit down, then in the next shot he is sat down, then walking to sit down again. (00:20:25)
The One Where The Stripper Cries - S10-E11
Continuity mistake: When Ross and Chandler are talking about who broke which pact in college (the girls they agreed not to date) they are standing at the drinks table. Chandler is holding a drink in his left hand and his right hand is in his pants pocket. The shot then changes to face Ross, Chandler does not remove his hand from his pocket, but in the next shot facing him his drink is in his right hand. He then places it on the table. (00:18:20)
The One With The Cake - S10-E4
Continuity mistake: When Monica's mum and dad are leaving the party, they are standing next to each other while her dad explains why he can not drive anymore. Her mum has both hands in front of her holding on to her purse, in the next shot one arm is around Monica. (00:13:50)
The One With Ross's Tan - S10-E3
Continuity mistake: In the scene where Joey and Rachel are sitting on the couch in their apartment after they decide their relationship is hopeless Rachel puts her head on Joey's shoulder. Her hair is on her face but when she lifts her head up in the very next shot her hair is now behind her right ear which she couldn't have done because her hands never left her lap. (00:22:00)
The One Where The Stripper Cries - S10-E11
Continuity mistake: When the girls and Mr Goodbody are talking about paying him the three hundred dollars, the top buttons of his shirt are ripped open. Half way though the scene this changes to only one button being open and his shirt looking neat and pressed, as if he had not started his strip yet. (00:13:25)
The One With Ross's Tan - S10-E3
Continuity mistake: At the start, the lid on Joey's bottle is on and off depending on the shot. (00:00:20)
The One Where The Stripper Cries - S10-E11
Continuity mistake: When the stripper first walks in, he is wearing a uniform with a circular badge. A few moments later the badge is not circular, it is a shield type and shape and the uniform appears to be different.
The One With The Cake - S10-E4
Continuity mistake: When Jack and Judy leave Joey's apartment, there is a birthday banner on the counter that has fallen off. When Monica, Chandler, Joey and Phoebe are racing the toys to see who gets to go, the banner is back on. In this time no-one has fixed the banner as there is not enough time for them to do so off camera and the people on camera don't fix it. It's most clear that it's back on when Monica is saying, "Technically, our dog never crossed the finish line". (00:14:05 - 00:17:05)
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.