Check out http://www.pwnadventure.com/

"Pwn Adventure 3: Pwnie Island is a limited-release, first-person, true open-world MMORPG set on a beautiful island where anything could happen. That's because this game is intentionally vulnerable to all kinds of silly hacks! Flying, endless cash, and more are all one client change or network proxy away. Are you ready for the mayhem?!"

"Pwn Adventure 3 was originally during Shmoocon 2015, from January 16-18, 2015. While the CTF is now over, we are still running the servers in a limited capacity so others can try it."