Valve Time Tracker
From Valve Developer Community
This page is for tracking projects which have been given Valve Times but have yet to establish their Actual Time equivalents.
Project Given Valve Time(s) TF2 class updates on the Xbox 360 "Before the end of 2008."
Valve have now said they can't due to memory limitations on the 360
Half-Life 2: Episode 3 Christmas of 2007 SteamOS "Downloadable soon."
End of the week (12/13/2013)
Steam Machines "during 2014" "some truly big surprises" http://www.teamfortress.com/post.php?id=12146 2014