OverTheWire is a fantastic website that provides wargames to help the next generation of cyber security professionals practice security concepts. A wargame is a security challenge in which the competitors must exploit or defend a vulnerability in an application or system, or gain or prevent access to a system.
The wargames hosted by the OverTheWire community are split into levels. You start at level 0 and in order to advance to the next level competitors need to acquire a password by exploiting a vulnerability. The kind of subjects tested include reverse engineering, server side web security and low level programming. Even if you don't directly use these skills on a daily basis, working through these wargames is a great way to learn how software works underneath the often enshrouding GUI.
I have been slowly making my way through the wargames and have decided to share the resources and knowledge I have gained from attempting them. Below you will find links to the first level of each of the wargames I have written up and from there you can move through the rest of the levels.
I hope you'll enjoy struggling through these wargames as much as I have!