The One With Ross's Library Book - S7-E7
Audio problem: When Janice is groaning about Clarke sanding her up, the second "Oh" is obviously pre-recorded and the third "Ah I j..." is audio from the next closeup shot that hasn't been cut to yet. On top of this, her mouth moves on neither of them. (00:12:15)
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.