Device-specific hardware tends to get overlooked by the third-party development community, but the S Pen from Samsung's Note phones might be the exception. There are a lot of Note users out there and it has a stylus that's actually worth using. Samsung is now offering game developers a way to better utilize that feature with the Unity Extension SDK, which can be downloaded from Samsung's developer site.
In case you're not aware, Unity is a 3D game engine that's used by a number of popular titles. The new SDK will allow developers to accept input from the S Pen. The SDK provides devs with access to SCanvasView in their games. Users will be able to use all the S Pen features like pen brush, eraser, fill bucket, color picker, image insertion, undo/redo, and texture mapping. This allows the things you draw to be incorporated into the game immediately.
This is just the first release of the software, but there might be enough Galaxy Notes out there to attract some developers. It would be cool to see the S Pen utilized in third-party apps, and this is a good move in that direction courtesy of Samsung.