After finishing Punch-Drunk Love in 2002, Boogie Nights director Paul Thomas Anderson found himself fumbling for a follow-up. ''I was really sick of the way I was writing,'' he says. ''Everything looked as though I had written it, and that was a horrible feeling.'' Purely as an exercise, Anderson decided to adapt a scene from a novel he had just discovered: Oil!, Upton Sinclair's 1927 take on the grueling, greedy business of prospecting for black gold in California. ''It was a buoy, just to keep writing,'' says the director. ''I didn't think I would end up adapting the [whole] book, but it turned out that way.''