BUSINESS 'Kingdom' could take boxoffice crown 5:00 AM PDT 4/17/2008 by Empty , AP FACEBOOK TWITTER EMAIL ME Empty Martial arts fantasy "The Forbidden Kingdom" from Lionsgate and the Weinstein Co. looks likely to bow at No. 1 this weekend with up to $20 million. FACEBOOK TWITTER EMAIL ME Empty THRnews@thr.com @thr AP THRnews@thr.com @thr