5x18 "The One Where Rachel Smokes"

Rachel tries to take up smoking so she'll feel more included at work with her boss and co-worker. Joey auditions for a soup commercial with Ben playing his son, however the director pairs Ben with another father and eventually Joey is left in the uncomfortable position of going up against his friend's son. Monica and Phoebe throw a birthday party for Rachel, and Phoebe gets upset about Monica taking charge, so when they agree to work together, Phoebe goes all out, when she is in charge of cups and ice.