Melt chocolate chips in medium saucepan over low heat until smooth. Remove from heat. With wire whisk, beat in margarine, heavy cream and vanilla until smooth. Place in bowl; refrigerate until firm, about 3 hours, stirring occasionally. Shape teaspoonfuls of mixture into balls and roll in cookie crumbs, chopped nuts, coconut, melted white chocolate or colored sprinkles until well coated. Store in airtight container in refrigerator. Makes 21⁄2 dozen.