Series 4, Episode 5
Phoebe has caught a cold but it works out to her advantage when it helps her sing. Rachel's new boyfriend is literally just that, whilst Ross tries to convince Rachel that his new girlfriend is really something special when in reality he is simply her babysitter. And speaking of girlfriends, Chandler gets majorly jealous when he falls in love with Joey's new woman.
Apart from the whole Ross vs Rachel thing being ridiculously childish this is actually a great episode.