Billy Bob Thornton suffered for his art in new movie SCHOOL FOR SCOUNDRELS - by playing tennis with Napoleon Dynamite star Jon Heder. The movie star plays a self-help guru trying to steal the object of Heder's affection from him, and the two teamed up for a doubles tennis game that proved to be a very painful experience. Thornton explains, "I really did get hit. At first I thought, 'They're just tennis balls,' but if you get whacked by a tennis ball going that fast it's not real pleasant. "I was never a tennis player. I got popped with the racket a couple of times in the head. He (Heder) was supposed to miss and he didn't a time or two. "It wasn't that bad because I've done movies before where I got seriously injured so if you got to get injured I think a tennis ball is a good way to go."