I got involved with Octave on the Winter of 2010, at the end of my first year as PhD student. My project involved using a Matlab piece of code written by a collaborator but I refused to use it, I wanted free software. So I convinced the collaborators to release it under GPL and ported it to Octave (released as frapinator, but I really should go back and write it properly).
Since then, I have contributed to Octave many times, became maintainer of the Octave Forge project and its image package. While I have no formal education in programming or computer science, it was the freedom of Octave and its community that allowed me to learn so much.