I have recently acquired GameMaker by Yo Yo Games for cross-platform game development. Among the supported platforms are Windows 8 and Windows Phone 8!
This gaming tool allows anyone with decent computer skills to develop a game rapidly. I recently lead a group of students (many who had never written a single line of code before) to create a simple game in one hour. I could not believe how much the students accomplished in such a short period of time.
I highly recommend GameMaker, and suggest you start creating your game today! There is a free version of GameMaker available to download now. However, I strongly suggest that you buy GameMaker:Studio Professional while it is 50% off (offer ends January 4th 2013).