Today at San Diego Comic Con, Fox Digital Entertainment revealed Firefly Online, a social online role-playing game based on Joss Whedon's cult sci-fi TV series Firefly. It is currently in development for iOS and Android smartphones and tablets, and should be releasing in the summer of 2014. On the YouTube page, the description says that it'll initially be available for smartphones and tablets, so maybe there's a chance that it comes to PC later on.
FireflyOnline is being developed by QMXi and Spark Plug Games. In it, players take on the role of captain, recruit crew members for their ship, and take on missions, all while interacting and trading with other players. It also features customizable ships and cross-platform play.