That website will not help you to become a hardcore hacker. The challenges are okay, and nice for beginners, but often not _very_ realistic. (I often use 0days in Web Applications, where I may have to create a duplicate of the target, and make it as realistic as possible and of course anticipate various security controls.)

If you want something hard, go for Cracking the Perimeter by Offensive Security and do the OSCE test. That will measure "how advanced" you are in your hacking abilities. Same with OSCP. If you can complete OSCP, you're a hacker, if you can complete OSCE, you're quite good imho. (The exam requires a high amount of creativity, skill, and pain resistance.)

For beginners, there's a lot better resources. The reason why I say that, is because A LOT of these challenges are way too unrealistic, such as but not limited to various "Cyber Challenges", offered by a large amount of companies and organizations each year to find potential pentesters.

So what are the better (free) resources?  If you're going into "website hacking" aka Web Application Security:
1) Learn all the fundamentals such as: HTML, CSS and basic JavaScript.
2) Learn PHP or ASP (or any other server language that serves websites, but PHP is often the easiest and most used choice.)
3) Learn how to find vulnerabilities in PHP code, write vulnerable code yourself, exploit it, write a patch, enjoy.
4) Download various web applications, preferably not widely used ones as they are often more secure. Install these, fuzz them or review the code and find 0days in them.
5) Use that knowledge responsibly. It's that simple, but it takes time to become good at it.

If you just want resources, try the forums at intern0t.net, the Metasploit Unleashed project by Offensive Security, and SecurityTube. HackThisSite has indeed existed for a very long time, and so has Myspace, that doesn't mean it is realistic to use.  No offense intended to any parties.

CTRLS, please do not feel sorry, the site that you mention is ok (I used in the past), the thning is that normally when somebody suggest a site other people wants to know about that site and how to progrees in the ethical hacker arena. So MaXe try to give more info

alright i just thought you were trying to talk shit or put me down....i was just trying nto help other

hey do you know any website sites where i could download the language C

Tough challenges, but no bad opinions! 

If you want something fun, look out for challenges by Offensive Security:
http://www.information-security-training.com/blog/
http://www.offensive-security.com/blog/

And perhaps more HaXx.Me's will be coming soon:
http://forum.intern0t.net/intern0t-contests/

(You can watch some of the solution videos at http://intern0t.blip.tv )

HackMe ;-)

List of more similar good apps:
- HackMe Bank
- MackMe Books
- WebMaven
- WebGoat

WebGoat is made by Owasp and is quite good, however at some points, not 100% realistic and it could work better, but overall it's quite good.