I have always enjoyed trying to gain access to things I'm not really supposed to play around with. I found Hack This Site a long time ago and I learned a lot from it. The issue I have with HTS is that they haven't updated their content in a very long time and the challenges are very similar. I'm no longer 13 and I want bigger and more complex challenges.
Also, are there any big social engineering competitions besides the one at Def Con?
- Over The Wire They have lots of small hacking challenges like: analyze the code, simple TCP communication application, crypto cracking.
- We Chall We Chall is similar to Over The Wire. Lots of challenges. They also have a large list of other sites with similar challenges.
- Smash The Stack
- DC3 Is the DOD:s Forensic Challenge. It's an annual competition with different scenarios that you gain points for solving.
- NetWars Offers tournaments at some conferences. And one longer challenge over 4 months. With scenario challenges.
- Cyber Security Challenge Needs description
- US Cyber Challenge Needs description
- Codegate Quals
- iCTF iCTF is a capture the flag contest held once a year.
- Hack.lu CTF 2012
- Defcon Quals
Other list like this one:
Other interesting sites:
Please help me add more to the list.