Here's an example.

The proliferation of companies like Steep Creek Media, which acts as a middleman between districts and would-be advertisers, has made it simpler for schools to get into advertising. Steep Creek offers an attractive proposition for schools — and business is booming, according to its owner and founder, Cynthia Calvert, who represents 35 districts and has had to turn down handfuls of clients.

In exchange for what usually amounts to a cut of 40 percent of the profits, the company lures potential advertisers with a diverse menu of placements: on buses, textbook covers, in-school television monitors, scoreboards and Web sites.

Or try this story.

Instead of placing ads up, some companies provide teachers with curriculum kits that mix educational lessons with frequent references to their products or corporate name. For example, in some communities, children use mathematics worksheets with Disney characters and when done see clips from the video. A nonprofit research group, The Milwaukee Center for the Analysis of Commercialism in Education, recently discovered that these corporate-sponsored classroom materials often subtly steer class lessons in directions advantageous to the sponsor.

Or, just google "Scholastic coal curriculum." Here's a summary:

Environmental groups are going after the world's largest publisher of children's books for teaming up with the American Coal Foundation to produce "The United States of Energy," a lesson plan designed for fourth-graders. The foundation, online at Teachcoal.org, is devoted to creating "coal-related educational materials and programs designed for teachers and students." …

The magazine Rethinking Schools published a scathing critique of the lesson plan in its latest issue, accusing Scholastic of producing "propaganda for the coal industry." They argue that the material "lies through omission" because it doesn't include problems like warming the planet, destroying mountain ranges, killing miners, or causing respiratory problems, to name a few. …