California Open Source Textbook Initiative
While granted California is not exactly mainstream America, it represents a healthy proportion of the American populace, and has proven to be a wellspring of innovation. California's budget problems are well known and somewhat endemic, and pricey school textbooks for public schools play a small but significant portion of this to the tune of $400 million plus a year. Chronic textbook shortages have also been a issue.
Here's comes that “wellspring of innovation" bit. By creating and utilizing a database of open source textbooks for use in the schools, not only would they dramatically reduce costs, but they would also be able to provide more breadth of content at greater depth, as well as being to more quickly update the textbooks for current developments. Those pesky textbook shortages would also cease to be a problem.
This isn't a replacement of printed textbooks, far from it. This is merely an attempt to reduce the costs on the proprietary ends of things, as textbook prices have gone up astronomically over the years despite research that they could be produced every bit as effectively for significantly less, savings of around $200 million a year.
The content is planned to be made publicly available online as well, though not for public editing in the same way as Wikibooks. That being said, the textbooks are being created using the already existing open source project, Wikipedia, as a tool.
For more on the plan, including the phases of its development over the course of the next decade, check out the project website at OpenSourceText.org