1. Operation Sony

Date: April 2, 2011 
Victim: Sony Computer Entertainment 

Remember when a different Sony website was getting hacked every week? Or when the PlayStation Network was shut down for what seemed like a the second half of the NBA season? That all started with an attack by Anonymous on April 2. After Sony decided to take George Hotz to court for creating and distributing software that allowed PlayStation owners to run homemade software on their consoles, Anonymous launched #OpSony and took down the PlayStation Network. The rest, as we saw, was history.