King Corn feels like the most ambitious state fair science project ever -- and, at the same time, I mean that as a compliment, I assure you. Most documentaries, most journalism and most bar-chat could use a shot of the kind of fact-checking, rigorous method and clearly-communicated conclusions you find in a well-tuned science fair exhibit. Two university pals, Curt Ellis and Ian Cheney, take a cross-country road trip; being nerds, they keep track of their meals -- and, being total nerds, run their hair through a spectrogram to see what that says about what they've been eating. It turns out they've been eating mostly corn -- so the two go from Boston, Mass. to Iowa to grow an acre of corn. They have no training in agriculture. They're just curious.