This past Saturday, Nintendo announced a sequel to New Super Mario Bros. coming to the Nintendo 3DS this August. The game, fittingly called New Super Mario Bros. 2, will be a "traditional side-scrolling adventure game" that's being created for pick-up-and-play sessions for players of all ages and skill level.
Unfortunately, Nintendo didn't share any more details on the title. They did release this packet of screenshots, however. Take a look (click each to enlarge):
Yup, it looks like a Mario game. But it's worth taking note of the "P-Wing" suit in one of the shots, which appeared last in Super Mario Bros. 3 and allowed Mario to fly for an unlimited amount of time. Looks like it's returning for this game.
We'll have more on New Super Mario Bros. 2 when Nintendo passes it along.