In Act 1, Scene 2 of Romeo and Juliet, why does Romeo want to go to the Capulet's party and why does Benvolio want to go with him?

In Act I
Scene 2,andcome across Capulets servant, who is charged with inviting the guests to Capulets
ball; however, he cannot read the guest list, and must ask Romeos aid in the matter.  In this
way the two Montagues learn of the ball and of the many women who will be there €“ Signior
Martino and his wife and daughters, some beautious sisters and lovely nieces €“ and of
course Rosaline, Romeos lost love, destined for the nunnery rather than his arms.  After Romeo
has read the list, the servant invites him and his companion, on the condition they be not of
the house of Montagues.

When Romeo and Benvolio first come onto the scene,
Benvolio is trying to comfort Romeo after losing Rosaline.  He argues that all his cousin need
do is find another lover €“ "Take thou some new infection to they eye,/And the rank poison
of the old will die."  And yet Romeo will have none of it, preferring to be a prisoner of
his misery.  So, when they are invited to Capulets ball, the event falls perfectly into
Benvolios attempts to distract Romeo.  He states that at the party, Rosaline will be surrounded
by all the admired beauties of Verona, and when Romeo sees her compared to such beauty, he
will forget her instantly, and see how ignorant he had been for loving her. 

Benvolio wants to go to the party to end Romeos moping heartache €“ he asserts proudly
that when Rosaline is weighed against the other many women at the ball, she shall scant show
well that now shows best.  Romeo, the hopeless romantic, will not be swayed by this argument,
but avows that he will go along€¦to rejoice in splendor of mine own.  He will go for his own
reasons €“ likely to see Rosaline again. So really, it is Benvolio who desires to go to the
party, and who persuades Romeo to tag along in hopes that the feast will raise his spirits.