There are undoubtedly lots of selfish reasons, but one of the reasons I spend time on free software is that I see it as a gift from me to you.
Why would I want to give you a gift? - it's because I'm grateful for two gifts I have been given.
First, I have been given a massive world of fantastic software I can use freely, created by the Free Software and Open Source community.
The second gift I have received is from God, whoever that is. As far as I can tell there is some kind of good person at the heart of the universe, and it seems worth trying to know them, frustrating as that can be. Sometimes I even feel like I do know them in a vague sort of way. I hope I see a sort of heart-opening that can happen, meaning I can start learning to care for people, even when they are not like me.
As far as I can tell, that makes me a Christian. I mean, I go to church and learn loads from the people there about who this person is, and how to do the heart-opening thing, so I guess I am.
If you'd like to find out more, feel free to contact me.