I see on many sites including here people making threads about a site that they found and which they wish to share with others. I have nothing against that but it would be much better to include at least 10 sites that you have found interesting over the past month or year. So here is a compilation of sites that I have been colecting for more than a year. Some of them I have even picked up from your posts if you do not mind.
This post has now been updated for the second time. It was about time since the last time it was updated was back in 2007. So some major revision has taken place.
If I may add it was not easy. Today most people have learned to use google to find resources. Still this is my list of websites and it has dramaticaly changed over the course of three years to that is in part what I am updating.

Random.
Now days I visit two websites on a daily basis. I need to keep up to date with linux distros and piracy issues:
http://distrowatch.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
http://torrentfreak.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Talking about torrents the choice of torrents sites is way beyond the scope of this list. To mentione just a few of them:
http://www.monova.org/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (good place for pron)
http://thepiratebay.org/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (I am sure you never heard of this one before)
http://1337x.org/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (for leet nerdy peoples like us)

So much for the nice weather when it is going to be raining torrents. I suggest you use rainmeter:
http://rainmeter.net/RainCMS/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
If you are looking for a trojan I advise you to download it from the developers site and not just some place where you are not sure if it has not been tempered with. One trojan/site that I find good is:
http://www.poisonivy-rat.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Now if infecting other peoples comps with trojans is a bit too much for you maybe you need some additional training/bost. Some websites that help to put you on the desired road:
1. http://www.slavehack.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (This site is a virtual hack simulation game.)
2. http://www.blind-dice.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (Another site dedicated to internet security challenges.)
3. http://www.runescape.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (The all time favorite of all geeks/nerds)
4. http://www.hackthissite.org/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; (They have really done a nice job with the layout)
Now if that is not your idea of fun but you still want to play with some thing you may want to look at. Firefox has a range of scripts to enhance webbrowsing with the greasemonkey add-on:
http://userscripts.org/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Do you have an old USB key you do not use any more. How about installing some porable apps on it:
http://portableapps.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Now I got one link for fun. I created this one a while ago:
http://suck-o.myminicity.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Seems like we are on stage for: increasing security. Some thing we are good at.