It's not uncommon to hear of Apple being sued for patent infringement. As the saying goes, if you live by the sword, you die by the sword. It is, however, uncommon to hear of Apple losing, at least somewhat. In 2012, it was found guilty of infringing on VPN patents held by a certain VIrentX, a "patent holding" company in Nevada. Thank Apple's lucky stars that its damages and royalty payments were overturned. But more than three years later, VirnetX has taken Apple back to court. And this time, it wants half a billion dollars.