‘STUDIO 666’ Rated R for strong bloody violence and gore, pervasive language and sexual content. What it’s about: The Foo Fighters hole up in a haunted Encino mansion to record a new album, though they don’t realize the home is filled with the murderous spirit of a ’90s rock band that perished there. The kid attractor factor: Younger folks who are fans of the band might be interested in this horror comedy. Good lessons/bad lessons: Don’t go in the basement! Violence: Some extreme gory violence and all manner of creative killings. Language: Swearing and strong language throughout. Sex: Referenc…