Edubuntu

Edubuntu is a grassroots movement, we aim to get Ubuntu into schools, homes and communities and make it easy for users to install and maintain their systems.

Debian-Edu

Debian-Edu (also known as Skolelinux) is a free and open source software project founded in Norway, now supporting all languages present in Debian. Its name is a direct translation of “school linux” from Norwegian, skole derived from the Latin word schola.

Fedora Education Spin

A special selection of applications related to educational and scientific purposes based on the Fedora distribution.

Guadalinux-Edu

Guadalinex-Edu is a custom Ubuntu spin deployed in Spanish schools.

OpenSuse-Edu

The openSUSE Education project tries to support schools using openSUSE, create and describe additional software-packages for educational projects and create an live CD for the regular openSUSE distribution.

Qimo for Kids

Qimo4kids is a kid-friendly desktop environment built entirely with free software. Qimo comes pre-installed with educational games for kids; TuxPaint, eToys, GCompris, Tuxmath, and Tuxtyping.

Uberstudent

Uberstudent is another Ubuntu-based educational distribution which aims at secondary and higher education. There is also an edition that runs the lightweight LXDE desktop environment that is meant to fit on a single CD.

Ubermix

http://www.ubermix.org/

Ubermix is extensively used in schools. The system was designed to store user data and software in seperate partitions. So, in case the computer malfunctions, the user can wipe out the operating system and resotre fresh copies quickly. From Ubermix founder, Jim Klein, in an Opensource.com interview:

Ubermix comes pre-loaded with a number of applications for education, productivity, design, programming, Internet, and multimedia construction. Education oriented applications like Celestia, Stellarium, Scratch, VirtualLab Microscope, Geogebra, iGNUit, and Klavaro, as well as educational games like TuxMath, TuxTyping, gMult, and Numpty Physics all bring with them plenty of opportunities to learn.

Internet applications we all know and love, like Firefox, Thunderbird, Chrome, Google Earth, and Skype are all there. Common productivity apps like LibreOffice, NitroTasks, Planner Project Management, VYM (View Your Mind), and Zim Desktop Wiki are too. Kids interested in design will find the GIMP, Inkscape, Scribus, Dia, Agave, and even TuxPaint for the younger ones. And apps like Audacity, Openshot, Pencil, and ffDiaporama help round out the media offerings. These, and many more, make Ubermix a powerful launchpad for student creativity and learning.

Sugar

https://www.sugarlabs.org/

Sugar was designed for the One Laptop per Child program. It is an easy to use and kid-friendly operating system. Children who love exploring will figure out things quickly in this environment, even if they cannot read or write yet.

From Sugar Labs:

Information is about nouns; learning is about verbs. The Sugar interface, in its departure from the desktop metaphor for computing, is the first serious attempt to create a user interface that is based on both cognitive and social constructivism: learners should engage in authentic exploration and collaboration. It is based on three very simple principles about what makes us human.

endlessos

https://endlessos.com/

The Endless Operating System is simple and easy for anyone to use. It is fully equipped with the essential apps to work, learn, play and connect.
All for free.