[Blake]

Hackthissite - http://www.hackthissite.org
A nice site (even though it has been having problems recently) including basic web challenges, "realistic" missions, basic cracking and encryption challenges.

ngsec - http://www.ngsec.com
A great website, with some tough final challenges. Including SQL Injection and some Buffer overflow challenges.

Try2Hack - http://www.try2hack.nl
One of the most well known hacking challenge sites, its levels are basic and ideal for those new to security.

Hackerslab - http://www.hackerslab.org
A great site with levels based around unix security, you'll either want to use linux or have a copy of putty to complete any of these challenges.

SlyFX - http://www.slyfx.com
A great challenge site, starts off with some basic maths and moves onto solving application problems (starts with some basic debugging and moves onto solving stuff)

Mod-X - http://www.mod-x.co.uk
Never completed this site, got a little bored with it. But on the whole rather good, if you've played the game uplink it's that sort of story (i think, as I said, never really played it I got bored at lvl3 :))

HackMe @ Elderson - http://hackme.elderson.net
Only a few challenges, but they are interesting ones.

Mindlock Security Challene - http://mindlock.bestweb.net/join.php

Zebulun Challenge - http://www.cyberarmy.com/zebulun/

Root Hack - http://www.roothack.org/

DataFort - http://hack.datafort.net/

HackNull - http://hacknull.com/

Digital Evolution - http://wargames.unix.se/

Osix Challenges - http://www.osix.net/

H4cherx Challenges - http://www.h4ckerx.ne

The Black Sheep - http://www.bright-shadows.net/

0penhack - http://www.0penhack.com/

ISATCIS - http://scifi.pages.at/hackits/

"The Game" - http://lightning.pro...g.com/~thegame/
Real applets which have been used in the real world, all client side editing.

HackQuest - http://www.hackquest.de/

BigContent - http://bigcontest.securityhack.net/ - In French

hackerss.com - http://www.hackerss.com/ - Spanish

izhal - http://www.izhal.com/ - Spanish

Boinas Negras - http://www.boinasnegras.com/ - Spanish

Hack4u - http://www.hack4u.nl
Very poor site indeed, the "staff" are script kiddies pretending to be hackers, avoid at all costs.

Thanks Tyrano, Player_0, usch, gman24, Sigm@, sp4rk, darkslaker and Dreamcatcher for some additions to the list.

http://mindlock.bestweb.net/join.php
http://www.cyberarmy.com/zebulun/
http://www.hack3r.com
http://www.roothack.org
http://hack.datafort.net/
http://www.hackingzo...eb_wargames.php
http://warsql.hackingzone.org/
http://hacknull.com
http://www.elitehacks.de/
http://www.bright-shadows.net
http://wargames.unix.se
http://www.h4ckerx.net/
http://www.osix.net/

http://hackergames.net
^probably the best wargame portal...100+ different sites/games etc.

If anyone has any they'd like me to add, just give me the name, link & a
brief description and i'll add it - Let's see if we can get a nice list going. Anyone wanting to see a complete archive check out http://hackergames.net/