cK-12 Foundation

CK-12 will provide open-source content and technology tools to help
teachers provide learning for students in a global world. Free access
to high-quality, customizable educational content in multiple
modalities suited to multiple student learning styles, levels, resources
and use content acceptance will allow teachers, students and others to
innovate and experiment with new models and modalities of learning.
CK-12 help students and teachers alike by enabling rapid
customization and experimentation of teaching and learning styles.