Hot on the heels of Coachella, metal music's biggest names — Metallica, Slayer, Megadeth and Anthrax — are set to invade the Empire Polo Club for over seven hours of head-banging mayhem. A sighting of all four acts in the same set is as rare as a snowball's chance in — well, you know where. Empire Polo Club. Ave. 51, Indio. 2 p.m. Sat. $99. http://thebig4festival.com.