In the not-to-distant future, Wii U owners may be playing Super Mario Galaxy — at least, according to a recent listing by the ESRB:
Originally released on the Wii in late 2007, the platformer has been recognized as one of the best games in the generation. And although Super Mario Galaxy has been released for Wii U owners in Japan (since May 31, 2015) and the sequel Super Mario Galaxy 2 has been available for Wii U owners worldwide since last January, there had been no official announcement regarding a North America release.
Early ESRB listings have consistently been semi-reliable methods of predicting upcoming game. While there is no way to know when the title will release, games like Terraria and Slender: The Arrival received early ESRB publications before official announcement.