When I was browsing Moiz's post (
http://evilzone.org/found-it-on-the-webs/compilation-of-hacking-related-resources-2/) on hacking resources, I found this little gem.
http://www.overthewire.org/wargamesI don't take any credit at all for finding this, if you enjoy it please visit Moiz's thread and give chuck that guy a cookie.
Since he had such an amazingly large list some of you may miss this site so I just wanted to bring your attention to it.
This website is a compilation of hacking challenges that are different from most that I've seen because most of the time you code small applications to complete the challenges. For example, on Lvl 0 in the Vortex Challenges you have to connect to a port on their server to receive 4 numbers and then add them and send it back to get a user/pass. You can then SSH to that server with said credentials.
Very cool.
Enjoy.