In the action comedy "Tropic Thunder," a group of actors shooting a war movie is led by Tugg Speedman (Ben Stiller), a pampered action superstar, Kirk Lazarus (Robert Downey Jr.), an over-the-top Australian-born method actor who has gone to extremes to get into character, and Jeff Portnoy (Jack Black), a gross-out comedy star. - Actors shooting movie get caught in real conflict.