"Valve Time" has been used as an overall term to describe when a game from Valve is released; in other words, "when its done." This week, Valve announced that a DLC pack for their zombie co-op shooter Left 4 Dead 2 that was first announced in February 2011 will get its final and official release later this month.
The DLC will contain the all new campaign Cold Stream, made by Left 4 Dead community map creator Matthew Lourdelet. Valve was so impressed with his early work on Cold Stream that they decided to make it part of an official campaign pack that would also include the three remaining campaigns from the original Left 4 Dead. In March 2011, Valve released the first public beta of Cold Stream and has been testing it ever since.
Valve has announced that all of these campaigns will be released in their final state, for both the PC and Xbox 360 versions, on July 24th. In addition, Valve said that with this release, " ... all of the mutations will be available at all times. This will allow players to choose to match into games playing Taannkk!, Gib Fest, or even a user created mutation like Confogl." Valve also hints that there will be more surprises in store for this DLC pack.
Source: Left 4 Dead blog | Image via Valve