Nintendo's much-loved Mario & Luigi RPG series is set to return this year with Mario & Luigi: Dream Team. Set primarily within the sleeping mind of Luigi (a realm in which the oft-relegated brother sees hiself as a mighty hero), the game looks to make rather innovative use of the 3DS' lower screen.
By manipulating Luigi's slumbering real-world body with the stylus, it appears that the player can directly affect events withing the dream-word. It's just like Inception without the droning horn blasts. Possibly.
The game currently has a release window of summer.