Copacabana Beach! Where there will be FIFA Fan Fest, from June 11th to July 10th, with daily shows & a giant screen to broadcast all World Cup games. Rio was one of the cities chosen to host the Fan Fest simultaneously in Rome , Paris , Berlin , Sydney & Mexico City . An arena is being assembled for the public to watch every World Cup game, free.
Head on down to Centro and pick your world cup gear at Saara. I found this getup for my nephew back home, which is being modeled by his little sister: