See

 http://www.fastcgi.com/mod_fastcgi/docs/mod_fastcgi.html#FastCgiExternalServer

settings in

 oddb.org.conf.fcgi

something like

 FastCgiExternalServer /var/www/oddb.org/doc/index.fcgi -socket /var/tmp/ch.oddb.socket
 RewriteLock /var/lock/rewrite-lock

FastCgi seems to be slower than mod_ruby

 http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/35893

Redmine FastCGI config

 http://www2.redmine.org/projects/redmine/wiki/HowTo_configure_Apache_to_run_Redmine#Additional-Apache-Configuration

Tuning your webserver

 http://scottstuff.net/blog/2005/07/20/apache-tuning-for-rails-and-fastcgi

Another link with fastcgi and RoR

 http://hack.emilykwan.com/node/95

More

 http://serverfault.com/questions/106067/how-do-i-setup-apache-with-fastcgi-and-ruby