Security students can practice their skills with software like OWASP's webgoat or something similar to "hackthissite". Students interested in Operating Systems can study MINIX and PintOS, write shell scripts or study POSIX system calls. What would be the best course of action in order to practice Server Administration? Is there any such software/resource available, teaching you such skills with small lessons, or it is totally up to you? I've practiced live FreeBSD server administration and management of VMs (CentOS, Gentoo, Debian) under VirtualBox, but I always feel that this isn't enough and I must push myself harder. So, what would you recommend? What has worked for you?