23 - Spambot
The zombies are planning an invasion. But before they can start they want to scare the people by sending scary messages. Because zombies are not able to write letters they've developed a platform which automatically submits messages to guestbooks or comment platforms. A careless zombie lost his note about the spambot. So we found the URL of it. 
https://ctf.fluxfingers.net:2075/spambot/
Stop them! 
Write-up : http://xelenonz.blogspot.com/2012/10/hacklu-spambot-200-pt.html