Half Life 3

Discovered by members of NeoGaf, Valve filed a trademark for Half-Life 3 on September 29th, 2013.  With the recent announcement of SteamOS, is Valve preparing to announce the third installment of the Half-Life series?  Some are speculating that this might just be a case where Valve is renewing or protecting the name, but you can never be completely certain.

valve trademark

Source: NeoGaf