Vegas baby! It’s time to double-down on hard rock, as the Rock Vegas festival will take over Sin City for two days on Sept. 28 and 29 at Las Vegas’ Mandalay Bay Resort. The event will feature such topline acts as Rob Zombie, Shinedown, Marilyn Manson and Godsmack. But the talent lineup doesn’t stop there. Staind, Stone Sour, Papa Roach, Buckcherry, Adelitas Way, All That Remains, P.O.D., Art of Dying,