Stop Services on Ubuntu
Below is the list of services that will pretty much bring the server to idle and do nothing.
/etc/init.d/anacron stop /etc/init.d/cron stop /etc/init.d/apache2 stop /etc/init.d/mysql stop /etc/init.d/postfix stop /etc/init.d/courier-authdaemon stop /etc/init.d/courier-imap stop /etc/init.d/courier-imap-ssl stop /etc/init.d/dovecot stop /etc/init.d/privoxy stop /etc/init.d/rsync stop /etc/init.d/shellinaboxd stop
/etc/init.d/nagios stop