WarGames

Web-Based:
http://hax.tor.hu/
http://try2hack.nl/
http://hackthissite.org/
http://hackquest.de/
http://www.rankk.org/
http://www.caesum.com/game/
http://www.dareyourmind.net/
http://antica.bestweb.net/
http://www.daedlaus.com/sk00l/
http://hellboundhackers.org/
http://lost-chall.org/
http://www.net-force.nl/
http://thisislegal.com/
http://3564020356.org/
http://www.hacker.org/
http://www.javaist.com/rosecode/
http://listbrain.awardspace.biz/
http://securitytraps.no-ip.pl/
http://sabrefilms.co.uk/revolutionelite
http://www.enigmagroup.org/
http://www.osix.net/
http://www.bright-shadows.net/
http://www.mod-x.co.uk/main.php
http://www.hackertest.net/
http://www.trythis0ne.com/

Terminal Based:
http://www.overthewire.org/wargames/
http://www.smashthestack.org/
http://roothack.org/ (down)
http://intruded.net (down)
http://www.astalavista.com/hacking
http://hack.thebackupbox.net

Webapp Specific
http://demo.testfire.net/
http://wocares.com/xsstester.php
http://crackme.cenzic.com/
http://test.acunetix.com/
http://zero.webappsecurity.com/
http://ha.ckers.org/challenge/
http://ha.ckers.org/challenge2/