California -- Los Angeles has become the unofficial capital of storefront shops that sell marijuana in recent years, and so many have sprouted that no one knows exactly how many exist. But those freewheeling times are skidding to a halt. The City Council has imposed a moratorium on any new pot shops and is moving to regulate the existing ones. Users are feeling a chill, too, from a recent court ruling that allows California employers to fire pot smokers even if the marijuana is used at home and purchased under state law.