Alpha Protocol and Fallout: New Vegas, as well as the perpetually delayed/possibly dead Aliens RPG, Obsidian Entertainment is apparently working on a fourth, unannounced title. In an interview with GameBanshee, Obsidian's Feargus Urquhart said, "We have been working on another title for the last four months that we can't talk about yet."
According to the piece, the game is being developed on the company's internal engine, though Urquhart had, more or less, positive things to say about his company's experience with Unreal Engine 3. "Our engine, like Unreal, is a tool and different jobs can be done better with tools that are made for them ... there are things that our engine may never do as well as Unreal, but likewise there are things that our engine will do that will be better than Unreal," Urquhart says of the choice. Considering the rest of the interviews answers, we're fairly certainly that the game's not a new Neverwinter Nights nor Knights of the Old Republic 3. Guesses, friends?