The Rock in Rio USA Festival will take place over two weeks in May with designated rock and pop weekends. The rock weekend will take place May 8 and May 9 in Las Vegas. For those looking for a harder edge, May 9 has Metallica, Linkin Park, Rise Against, Hollywood Undead, Deftones, Sepultura, Coheed & Cambria and Of Mice & Men all part of the lineup.