2016 SANS Holiday Hack Challenge
The SANS Holiday Hack Challenge is a yearly learning event hosted online by SANS Institute. It is a great learning experience for anyone interested in information security or CTF challenges. This is different than other CTFs since they have an actual game world in which you can create characters and explore. They also provide great references and hints to the challenges.
A copy of my 2016 SANS Holiday Hack Challenge writeup can be found here