Dr. Geo is at heart a free software and it is pushing the open source educative paradigm so far it is even possible to study & to modify Dr. Geo from itself.
Related to education and free software, Christopher Whittum is writing a book: Energize Education Through Open Source. He presents a fraction of the free applications for education in a format that is approachable and that will awaken an awareness in the minds of teachers of an underutilized resource.
Follow an abstract of his book.
The focus of this project is to endow educators at all levels with the knowledge that open source alternatives to proprietary software and hardware exist and how this open source software and hardware may be obtained. This work does not attempt to cover every piece of open source software and hardware available, but merely proposes suggestions for integrating this technology. Furthermore it serves to provide a launchpad from which educators can conduct their own investigations to find open source technology that may meet their needs. The work is really a survey of open source technology.
The work progresses in a logical fashion, first discussing the Linux operating system. The second chapter addresses curriculum and how open source software can meet specific curricular standards. The third chapter focuses on productivity applications. The fourth chapter presents software that can be utilized as aids to learning. The fifth chapter addresses tools for organization. These include applications for individual and organizational use as well as software for collections management. Appendices present the GNU General Public License, cost-effective means to implement open source technology and how to play DVDs in Linux.