10. "Food, Inc." (2009)

Robert Kenner's argument that something's gotta give with the way food is produced for U.S. consumption has only been in theaters for less than two months, but it's already broken the top 50 for highest-grossing docs ever, and it's already affecting what viewers buy and eat. Expect it to get another push as the obesity epidemic becomes a major talking point in health care reform, or in a worst-case scenario, as food recalls increase.