During its E3 presentation Nintendo just announced one of the most compelling reasons yet to pick up a Wii U. Mario Maker is essentially a Mario Bros. game construction set for the Wii U, letting users build their own levels — either in the classic Super Mario Bros. style, or using the visual elements from New Super Mario Bros. U — and then play them. There's no pricing or hard release date just yet, but the game should arrive sometime in 2015. A leaked shot from Nintendo's E3 booth first gave us a hint that the project might be coming, but it's authenticity wasn't verified at the time. Of all the cool news that we've heard thus far at E3, the ability to build our own Super Mario Bros. worlds is right near the top of the list, and no doubt Nintendo is hoping it will help prop up those disappointing Wii U sales.