Okay for those who are tired from downloading vulnerable images and configuring a lab especially if you have only one computer , it s time to forget this pain and try to hack all these machines online
http://www.root-me.org/" onclick="window.open(this.href);return false;
there are tones of challenges in coding, crypto etc and most of the vulnerable images can be attacked online
The machines included are :
Metasploitable : all versions
Kioptrix : all versions
VulnVOIP
VulnVPN
Windows xp etc
have fun