I saw this question (How should I show relevant volunteer work on a resume?) which answers half of my question, but not the other half.
I'm a programmer that does some open source work (above), but also has an interest in Linux both professionally and as a hobby. In my work experience, I have zero experience with Linux, but I use it often at home and have built my own Linux From Scratch (LFS) on a computer.
According to some contacts of mine in the Linux-focused industry, if a potential employer were aware that I'd made my own LFS it would be, barring hugely negative items, an automatic green-light for an interview with the hiring manager.
As my resume currently stands I have a section for past education, past work experience, and then a 'technical tools' section that highlights languages, software packages, etc that I am comfortable with. Due to the importance, I'd like to put it higher up but I'm unsure of how to put it on in a way that shows I didn't do it for work, but is 100% relevant to the work I'm doing