by frag.machine » Wed Jun 16, 2010 12:42 pm
IIRC Nehahra comes with a SDK, QuakeC source code included. But the cutscenes are just hand-edited demos, I don't think there's much QuakeC-related stuff there.
I know FrikaC made a cgi-bin version of the quakec interpreter once and wrote part of his website in QuakeC 
(LordHavoc)