Corrected entry: When Rachel and Ross are pulled over by the Cop on the freeway, the Cop states that Rachel's starsign is Aquarius, based on her driving licence details. However, in series 4, 'The One with Joey's New Girlfriend', she tells Gunther that her birthday is May 5th. That would make her starsign Taurus.
Corrected entry: When the police officer is giving Rachel a ticket he sees her birthday, says "Aquarius", and she says yes. But in an earlier episode when Gunther is asking for people's birthdays Rachel says her birthday is May 5. To be an Aquarius your birthday has to be between January and February.