GNU/Linux, more commonly known simply as Linux, is a free operating system and gateway into a dimension comprised almost entirely of brain-**** and penguins.
Just The Facts
1. It's free.
2. It's stable and secure.
3. Assuming you chmod +x /usr/bin/firefox, install the proper libraries, and learn the correct incantation to make Flash work, you can use it to look at boobies on the Internet.
4. Ironically, the boobies you would be looking at have an 80 percent chance of being hosted on a server running it.
History
While Microsoft and Apple were started by nerds whose eyes had been replaced by cartoonish dollar signs, the Linux kernel is the fruit of one commie grad student's hobby in the early 90s. Originally designed as a clone of Unix to run on the creator's personal machine, Linus Torvalds released Linux (see what he did there?) to the then youthful Interwebs under the GPL (an Open Source license allowing software to be freely modified and distributed).
