Online challenges
Live
- Archives (Defcon CTF, GItS, Hack.lu, NDH, ...) http://capture.thefl.ag/
- Hack.lu
- rwthCTF 2011
- https://wiki.mozilla.org/Security/Events/CTF
- Ghost in the Shellcode
- http://ctf.forbiddenbits.net/?
- Plaid CTF 2012
- Defcon CTF
- ...
Permanent
IRL challenges
- Insomni'Hack
- Jurackerfest
- ...