The Grandaddy of all “Free and Open Source” Software is Linux.
Linux is an operating system like Windows or OS X, except it is free and open source.
If you are not already initiated in the FOSS community, here is a Charlie Rose interview with Linus Torvalds, the creator of Linux… He talks about how his intent was not political, that he created the OS for fun.
https://www.youtube.com/watch?v=jJ4y6p6xdmw