Super Mario 3D Land. In a recent Famitsu interview (translated by 1UP), Shigeru Miyamoto explains his role as "general producer" on the title, saying that he was uninvolved until about halfway through the project. "I kept my distance from the project at first, but became more deeply involved midway -- I don't think it'd be satisfying as a Mario game to everyone unless I made myself known on the little details," he says.
Miyamoto further details his work on the project, specifically citing his work as helping to "fine-tune the numbers" behind things like Mario's iconic jump or run speed. He also points out that Mario's upcoming 3DS game draws from the world of Super Mario Bros. 3, while the "New" Super Mario Bros. titles drew from Super Mario World's foundation. Neat!
"The New Mario series was an effort to get back to the core of it," he adds. "And this game is kind of an in-between -- it's 3D, but it's a Mario that lots of people can play." To that end, Super Mario 3D Land will feature a hint system akin to other recent Nintendo first-party titles, which Miyamoto teases briefly. But you wouldn't need such a thing, right?