the gift for Hanukkah
Joey wants to give his girl friend a gift for her birthday. He gets a pen at Office Max. -_-!!

Chandler: Huh-huh! You can't give her that.

Joey: Why not?

Chandler: Because she's not eleven! And it's not the seventh night of Hanukkah!

Q: Please tell me something about "the seventh night of Hanukkah".
I know a little about Hanukkah. It lasts 8 days. Childrens can get a gift each day. What kind of gift will they get? Is it very small, so Chandler said that?

Question

the gift for Hanukkah
Joey wants to give his girl friend a gift for her birthday. He gets a pen at Office Max.  -_-!!

Chandler: Huh-huh! You can't give her that. 

Joey: Why not? 

Chandler: Because she's not eleven! And it's not the seventh night of Hanukkah! 

Q: Please tell me something about "the seventh night of Hanukkah".
I know a little about Hanukkah. It lasts 8 days. Childrens can get a gift each day. What kind of gift will they get? Is it very small, so Chandler said that?

Answer

The 7th night is not special in relation to gift giving. This is typical "Friends" humor. It just sounds funny! Yes, the kids get small gifts every night. Chandler is telling Joey not to be so cheap!
And living in New York, which has a very large Jewish community, and most people there are aware of various Jewish holidays.