Whiskey Sour
Whiskey Sour was a game in development by Turtle Rock Studios. Although never officially announced, its existence was confirmed in February 2010 with the release of the Left 4 Dead level design documents (LevelDesignDocs.zip): the file Level Design Docs/pages/files/index_002.php contained a link to a Whiskey Sour category alongside Left 4 Dead and Team Fortress categories. The Left 4 Dead level design documents had been exported from an internal MediaWiki and apparently had not been completely cleaned up (the file Level Design Docs/pages/files/index.php does not mention Whiskey Sour for example).
At around the same time, http://www.turtlerockstudios.com/ was relaunched with a western theme - no doubt as a teaser to Whiskey Sour - but no explicit reference was made to Whiskey Sour itself. The Turtle Rock Studios website maintained the western theme until mid-2013, though the site had been advertising for CryENGINE for some time at that point, which was ultimately used for their next game Evolve.
While no details were ever released about Whiskey Sour, there is speculation that the game would have been something like a western-themed Left 4 Dead - not unlikely given that Turtle Rock Studios' subsequent titles Evolve and Back 4 Blood had similar game styles to Left 4 Dead, with a team of 4 players against an asymmetrical enemy.
