Richard Stallman
Richard M. Stallman (RMS) is the founder of the GNU project and the Free Software Foundation. He is the brains behind the GNU General Public License (GPL) and the GNU/Linux operating system. Stallman was part of MIT's Artificial Intelligence Laboratory in the 1970s, where he did a lot of creative computer programming (which he and his friends called "hacking").
He conceived of the notion of "free software" where the software is free as in "free speech", as opposed to "free beer". It is formally licensed as an alternative to the public domain. He as actively promoted forming a worldwide community of programmers and software users who can all equally share the benefits of new and improved software donated to the community. Stallman is also an atheist.