Open source software is poised to make a profound impact on K-12 education. For years industry experts have been predicting the widespread adoption of open source tools by K-12 school districts. They're about to be proved right. The impact may not yet have been profound, but it's fair to say that some open source systems and non-proprietary applications have laid a real foundation in K-12 for what many expect to be widespread adoption down the road. In this article, the author discusses some open source software and applications.