[Update]: Nintendo unveiled Mario Maker, a level-creation game that will be coming to Wii U in 2015. Check out the announcement trailer below.
[Original] Nintendo is planning to announce a game called "Mario Maker" next week at E3, if an alleged leaked photo of Nintendo's E3 show floor is any indication.
The image (pictured below) is a bit blurry and could be completely fake, but the prospect of a Wii U Mario game that uses the GamePad to allow users to create custom 2D platforming levels sounds too amazing to not be real. Then again, Nintendo is infamous for defying expectations.