THERE'S NOTHING inherently wrong with companies advertising their products, and documentarian Morgan Spurlock isn't going to try to tell you otherwise. But as advertising becomes ever more pervasive, and the delivery mechanisms more sophisticated, Spurlock set out to shed some light on the way it functions. His new movie, POM Wonderful Presents The Greatest Movie Ever Sold, investigates the often cloudy intersections of advertising and entertainment. And because we're talking about the filmmaker who famously took on the fast food industry by eating nothing but McDonald's for a month, there's a hook: This documentary about advertising is funded entirely by... advertising. With the same show-don't-tell approach he brought to Super Size Me, Spurlock sets out to create the world's first "documentary blockbuster"—novelty plastic gas station tie-in collectible cups and all.

Greatest Movie is about Spurlock's attempt to make the movie, as he clumsily explains to one skeptical exec after another in his effort to find sponsors for his film. It takes him a while—and his failed meetings make for hilarious copy—but eventually he begins lining up brands who, in exchange for product placement or a mention in the movie, will agree to kick in some funding. (Hence the movie's title—POM's in it for a cool million.)

In addition to offering a peek at how sponsorship deals are made, Spurlock considers the question of advertising from a handful of other angles, including a trip to São Paulo, which recently banned advertising in public spaces; a visit to a powerful Hollywood broker who can make or break a film with product placements; and a look at a Florida high school so desperate to offset budget cuts that they're selling ad space on anything they can. There's even an appearance from Ralph Nader, warning Spurlock about the possibility of accidentally selling his soul. But Spurlock seems to have his soul firmly in grip—the movie that ads paid for remains decidedly independent, thanks to his sly sense of humor, and his determination to shed light on the open secret that is advertising's influence on entertainment.