This one made me smile so I had to share it, there's a 25 year old bug that has just been fixed with seekdir() on
all BSD systems. For details, see
http://www.osnews.com/story/19731
And the actual patch for FreeBSD is now available:
http://www.nabble.com/i386-121656:--libc---PATCH--telldir-issues-td16019215.html
There's something wonderful about the open-source community and how problems get fixed... well eventually

Generally, BSD licensed projects freebsd (os), postgresql (database), dojo (javascript) have strong communities and in my opinion are great projects to be involved in.
BSD is a great license to study, modify and learn from software but also to collaborate with people from many different backgrounds, academic (research & students), corporate, hackers and so on... Happy BSDing