Crystal Castles and Simian Mobile Disco are set to headline this year’s Hard Fest in Los Angeles on October 31. The event, which takes place on Halloween at the Shrine Expo Hall, will also feature Soulwax, Boys Noize and LA DJ Steve Aoki with several more acts to be announced. The even will have a haunted-mansion theme and attendees are encouraged to wear Halloween costumes. For more information go to Hardfest.com.