Challenge Sites

http://www.zenk-security.com/

http://www.enigmagroup.org/

http://www.hackthissite.org/

http://securityoverride.org/news.php

http://hack-me.org/

http://www.wargame.kr/challenge/

http://lost-chall.org/

http://www.rankk.org/

http://www.hacker.org/challenge/

http://securitytraps.no-ip.pl/

http://www.dareyourmind.net/

http://www.bright-shadows.net/

http://hax.tor.hu/welcome/

http://www.mod-x.co.uk/main.php

http://www.mibs-challenges.de/ (german)

http://www.angelfire.com/ne/warp/

http://www.fatetek.net/challenges/index.html

http://alph4net.free.fr/index_challenge.htm

http://bigchallenge.free.fr/ (french)

http://www.infomirmo.fr/ (french)

http://www.mod-x.co.uk/main.php

http://www.caesum.com/game/

http://www.root-me.org/fr/Challenges/ (french and a great site, you can CTF and more (: )

http://w3challs.com/challenges/ (french)

http://www.newbiecontest.org/(french)

http://www.trythis0ne.com/

http://warzone.elhacker.net/ (spanish)

http://www.yashira.org/ (spanish)

http://www.net-force.nl/challenges/

http://listbrain.awardspace.biz/

http://www.osix.net/modules/geek/