The live http headers hacking was quite embarrassing for myself personally.
I had strong suspicions that a certain webhost a new client of mine utilized was both prone to attack, and not very forthcoming when past attacks had occurred.
So when I loaded their own website one day and found it full of ads for russian pornography... I confirmed my own bias that the webhost had been hacked... deleted the account, and moved everything over to AWS.
Changed all the passwords, freaked out a bit, etc...
Then I realized that it was just the extension I was running that injected those ads... d'oh!