I'm definitely not a developer but still I can do some C programming. In order to better understand ZFS I was playing/looking with its sources like adding my own "compression" to ZFS during Christmas (I know... but it was really late night and I didn't want to sleep) or later I wanted to implement RFE: 6276934 ability import destroyed pools as I think that in some cases this would be very useful. Additionally while playing with ZFS sources I already knew that implementing this should be really simple and I wanted to test how in practice it's easy (or not) to get your code integrated into Open Solaris (and later into Solaris). I signed Contributor Agreement, made necessary code changes, tested it then made manual changes. Now I requested a Sponsor - Darren Moffat offered his help. ARC case was needed as new options were added, code review was also needed and some paper work. Thankfully for me Darren took care of all of this - thank you. A while later my code changes were integrated (snv_37) into Open Solaris and will also be available in upcoming Solaris 10 Update 2. You can read more about my changes here.
The point is that it's easy to get your code integrated to Open Solaris and you don't have to be a developer - if you are for example a system admin and you find something annoying (or lack of something) in Open Solaris you can easily fix it and share your fix with others. And that's one of the main goals of Open Solaris, isn't it?
There are people afraid that contributing code to Open Solaris could actually mean worse code - fortunately it's NOT the case as even if you are not from Sun you have to submit your changes to code review, ARC, follow coding style in Open Solaris, etc. and fortunately for you (submitters) Sun people will take care of this - you just write changes. That way a high quality of code in Open Solaris is preserved.
Here you can find other bug fixes by non-Sun people into Open Solaris. There are quite a lot of them just after one year Open Solaris is here.