I was there in 2004, and I stayed in an apartment at copacabana beach in rio de janeiro.
there is plenty of parties out on the street, and at clubs. there is plenty of people you can party and meet there. I don't recall the name of the clubs out there but they are promoting them like crazy. You can just ask someone out there and they will guide you on the right direction.
You will definitely have a great time out there.