http://www.tomshardware.com/news/Obsidian-Entertainment-South-Park-RPG-THQ-Matt-Stone,14151.html#xtor=RSS-181
The developer behind Fallout: New Vegas and Neverwinter Nights 2 is currently working on a South Park RPG.
On Thursday THQ said that it's collaborating with Matt Stone and Trey Parker, creators of the animated TV show South Park, to create a role-playing game based on the highly-popular show. Simply called South Park: The Game, it will be developed by Obsidian Entertainment and land on the Xbox 360, PlayStation 3 and Windows PC in the second half of 2012.
Little is known about the RPG at this point, although THQ described South Park: The Game as "an epic role-playing adventure that will allow the user to befriend Stan, Kyle, Cartman and Kenny and explore the quiet little mountain town like never before."