The One With The Dirty Girl - S4-E6
Question: When Joey asks why he can't give Kathy the pen, Chandler says, "Because she's not eleven. And it's not the seventh night of Chanukah." What is Chandler talking about when he says, "It's not the seventh night of Chanukah?"
Answer: Chanukah is a Jewish celebration that occurs around the same time as the Christian Christmas. The celebration lasts for eight days and it is customary to give a small gift on each of the eight days. There is no special gift required and the line about it being "the seventh night" of Chanukah is just Chandler's sarcasm.
The One With The Dirty Girl - S4-E6
Question: Monica: "I can cook and you can take care of the money." Phoebe: "Oh! It will be like I have a wife in the 50's!" What did Phoebe mean? (00:18:50)
Answer: Exactly as she said - in the 50s it was near-universal for husbands to work and be the sole breadwinner/handle finances, while their wives stayed home and managed the house, including cooking.
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.