If some don't know what Linux is: Linux is a Open Source computer operating system(Its kernel if being straight, but in daily conversation, the name Linux, usually stands for the whole OS with all utilities and tools.) Since Linux is OpenSource and modular, it is very flexible. You can build large variety of different op systems for different purposes and for different platforms.. Or for different taste. There is already hundreds of Linux Distributions. The most common things that differs for regular users. is Desktop Environment (or maybe I should call it GUI(Graphical User Interface)?) Unlike in windows(Newer than 3.11), in Linux the Desktop Environment isn't build inside of OS. It is just an application(or collection of applications). You are not bound to use one and same Desktop Environment, u can chose the one u like most. There is high variety of them. like KDE
And many more, u may also chose not to use any of them, but just use only console. My favorite is KDE I have also slight acquaintance with Gnome and Fluxbox. Gnome and KDE are kinda in same level.. they're like rivals. Xfce and fluxbox aren't so functional but very simple and slight they working also for older computer. Example DSL
(damnsmalllinux) using fluxbox as Desktop Environment. It is a light weight Operating system that run with minimal hardware requirements.
My favorites Distributions are Mandriva
linux. I'm using Arch X86_64 now, I like it best. It requires little more advanced knowledge's, to install and maintenance. But it's not that difficult as Gentoo. I don't like Gentoo much, because it takes too much time to install and update, because it compiles everything. And also for educational purpose I think gentoo isn't that good as Arch for me. Things I learn by using Arch I can utilise also most of other Linux systems(probably also in other Unix like systems), but in gentoo there was too many gentoo specific commands/scripts.. Mandriva I like because it's really easy to install and to use. It was my first linux, I had(it was called Mandrake at that time).
Please see: http://futurist.se/gldt/
(Linux distributions, placed on a timeline.)
To advertise.. No no I mean, just to show how flexible and good Linux is,
There also exists PcLinuxOS ME(MuslimEdition)
, Ubuntu Christians Edition
, and Ubuntu satanic edition exists too
But EC forum, users might probably be more interested of Edubuntu(Ubuntu Education Edition)
It contains huge variety of Educational Games and Programs.. But I haven't dried any of those. They actually just contain some specific apps and themes..
PS. Linux is licenced under GNU GPL(GNU General Public License) which gives every person the freedom to modify and change, re-product and distribute it's code as long it is bound under the same license.. (That kind of licenses are sometime called also as copyleft which is a play from word copyright).