Heath Ledger in The Imaginarium of Doctor ParnassusThought Heath Ledger's Oscar-winning turn as the Joker in last year's 'The Dark Knight' was inventive? Wait'll you get a load of him in the 'The Imaginarium of Doctor Parnassus,' a mind-bending fantasy flick that marks his final big-screen performance. Watch the brand-new U.S. trailer after the jump.