I found I loved playing Serious Sam (it really captured the feel of the original Doom!), and hated working a cash register, so I wrote to the only email address I could find for Croteam (one of their artists!), and talked them into letting me do a Linux port. From there, I had some luck and started collecting other work... Now I do this sort of thing full time. I've touched pretty much every major game engine of the last decade, and worked with a lot of games.
Quoted in Robin Heggelund Hansen, "Porting games to Linux" hardware.no (2009-03-10)