Continuity mistake: In one scene, some of Saddam's troops pour oil all over Mark Whalberg's face (while forcing him to bite down on a CD so it runs into his mouth) in an attempt to torture him. The next scene, when he is rescued, he has nothing but the requisite smudges and "movie dirt" on his face. Apparently the Iraqis decided to clean the oil slick off of his face before he got rescued.
Trivia: When the scene where the cow is blown up was threatened to be cut due to money constrictions George Clooney paid for the effect out of his own pocket feeling it important to the scene. He was right, the scene was wildly popular with audiences. (Source George Clooney Biography at http://www.tiscali.co.uk/entertainment/film/biographies/george_clooney_biog/5).
Trivia: George Clooney and director David Russell got into a fist-fight when Clooney objected to the way Russell was treating some extras. In a moment of frustration, Russell lashed out and began berating the extras and Clooney stepped in to defend them. Later, Russell would say that he wouldn't make another movie with Clooney for $20,000,000. (Sources Clooney Biography at http://www.tiscali.co.uk/entertainment/film/biographies/george_clooney_biog/5 and IMDb).
Trivia: Tony Gardner, special makeup effects artist was under investigation by Arizona State Police and Missing Persons bureau for effects work done on "Three Kings" involving a bullet traveling through a soldier's body. Arizona State Police originally believed that bullets had been fired through a real human cadaver, and filmed with a high speed camera. The Missing Person's division thought that the "cadaver" was obtained by taking a homeless person off of the streets of Phoenix, Arizona. Eventually, Tony had to write a disclaimer describing how he had achieved the sequences with makeup effects technology so that Warner Brothers could hand or fax the disclaimer out to all of the people flooding their offices with inquiries.