Fallout: New Vegas. Without offering any specifics, the Bethesda Blog states that the update "resolves quest and scripting issues." Of course, doing anything to fix the game's many technical problems has to be a positive step, right? Bethesda is working on releasing the update for the PS3 and Xbox 360 versions of New Vegas "as soon as possible."
Apart from the patch, Bethesda has also released the G.E.C.K. Editor for the PC version of New Vegas, which allows players to create their own characters, locations, dialogue and game scenarios. You can grab it from the Fallout downloads page, and it should be available via Steam "shortly."