Answer:
Romeo and Benvolio crash the party wearing masks. They learn about the party quite by accident in Act 1, Scene 2. An illiterate servant has been sent out with a list of names of people he is to invite to the feast, and he is confused. He asks Romeo to read the list for him, and in this way Romeo his friend Benvolio learn that there will be "a fair assembly" at the Capulets' home. Shakespeare inserts some controversy between two Servingmen at the opening of Act 1, Scene 5, apparently for the purpose of showing that the Capulet household is in a chaotic state because of the big event.
