The Large Hadron Collider a.k.a the Atom Smasher a.k.a. Sh*t That Will Get You Killed was compromised by a team of hackers calling themselves Group 2600 of the Greek Security Team.
"We're pulling your pants down because we don't want to see you running around naked looking to hide yourselves when the panic comes..."They signed off:
"We are 2600 - don't mess with us."

GST made a bit of fun at the IT used on the LHC, describing the security technicians as "a bunch of schoolkids." Oof.
The hackers were able to upload a few files and were a small step away from gaining full control of the Compact Muon Solenoid Experiment, or CMS, which is basically one of the project's data collecting systems. They mentioned that they only meant to show how vulnerable the project was -- which they definitely did.
It's all fun and games until someone gets sucked into a black hole.
[ Via: via: telegraph.co.uk ]