For some reason, my CentOS server didn't want to reboot after I issued the reboot and shutdown -r now commands. All I saw in the /var/log/messages logs were:
Aug 25 13:34:32 voltage-out shutdown: shutting down for system reboot
Aug 25 13:34:33 voltage-out init: Switching to runlevel: 6
What would cause this? A hung process? How can I best troubleshoot this if it comes up in the future?