"The One Where Rachel Is Late" is the twenty-second episode of the eighth season of Friends, which aired on May 9, 2002.
Rachel is very frustrated with the fact that she's 8 days late, and she is starting to become extremely difficult to live with. She is moody, snaps at everyone, and makes everyone around her miserable. Ross in particular gets the brunt of her moodiness.
Joey only has one ticket to his big movie premiere. The others argue over who should get it, but Joey says he wants Chandler to come as a way of paying him back for his support over the years. However, Chandler falls asleep during the movie and Joey is angry. He attempts to pay Chandler back by writing him a check instead, but when he realizes how much he owes Chandler, he decides it's not a big deal and forgives him.
Monica and Phoebe make a bet that Rachel will have her baby. Monica keeps thinking it will be that day, and loses 3 days in a row. When Ross and Rachel find out about the bet, Ross is angry, but Rachel wants in on it. They go to the doctor and get some home remedy suggestions for how to speed along the labor. They try everything, from spicy foods to long walks, but the doctor also recommends sex. Rachel is so miserable that she wants to do it, but Ross is worried it will open up a can of worms. Rachel begs for some time, but eventually gives up and goes back to being moody and difficult. After Rachel gets too annoying for Ross to bear at all, he decides to try having sex. After only a second or two, Rachel's water breaks. Before Ross and Rachel leave the apartment they share a kiss.
Monica and Phoebe get the call to go to the hospital, so Monica wants to bet with Phoebe one more time. As Monica and Phoebe leave the apartment, Monica keeps trying to make bets like... if the baby is over 7 pounds and if it's a girl.