My Googling efforts have ended up with this: blog.unquiet.net/tag/osx/ (installing lighttpd on Tiger); blog.ideoplex.com/software/ (fastcgi patch for RoR); fastcgi.coremail.cn (a fastcgi replacement) & sqlrelay.sf.net; and www.linuxjournal.com/article/7922 (Ruby clustering with sqlite; not quite on topic but nevertheless interesting).