One of the more surprising things from Nintendo's conference (and this is a show that had Wii U) was the reveal of a brand new Luigi's Mansion game for the 3DS.
The game holds true to the GameCube original, that was one of that console's launch line-up titles. But Nintendo confirmed that there'd be multiple mansions to play through, hopefully expanding the lifespan of the gameplay, which was one of the biggest issues with the original game.
Check out the trailer and screens.