Assassin's Creed was released officially on April, 8, 2007; but it was available on warez and p2p sites about 2 months before that.
Needless to say, Ubisoft - who wasn't very happy with it - spent the past few months tracking the leak back to its source before filing a law suit against him.
Ubisoft managed to track the leak back to Charlotte, North Carolina-based Optical Experts Manufacturing (OEM), the company that it had contracted to reproduce copies of the game disc.
According to Ubisoft, OEM's "extraordinary breach of trust and gross negligence" allowed one of the company's employees to take a copy of the game home and leaking it to the internet. This happened because OEM ignored the security procedures they agreed to abide by.
In addition to sales lost to piracy, Ubisoft also claims that the leaked hurt their reputation. As a security precaution, Ubisoft included an intentional bug that caused the game to crash halfway through. The bug was then removed from the retail version, but it still made it way to several online reviews and spread through word of mouth, causing an "irreparable harm" to Ubisoft's reputation.
According to Ubisoft, Assassin's Creed was illegally downloaded more than 700,000 times, but sold 40,000 units only in the 2 months following it US release.
Ubisoft is suing OEM for copyright infringement, breach of contract, and negligence. It is asking for damages and legal fees relating to all three claims, in the amount of no less than $20 million.