Download and try the following OS, and give it a go.
OpenBSD is a multi-platform 4.4BSD-based UNIX-like operating system, and is fast, simple to install and secure “out of the box”.
A good introductory book for OpenBSD is the “OpenBSD Command Line Companion” by Jacek Artymiak. It walks you through an install and an intro to OpenBSD.
Other books on the OS are: