Super Mario Galaxy 2 is coming to the Nintendo Wii. Soon, even. Here are a bunch of ads. Better yet, a compendium.
That's Kazunari Ninomiya and Masaki Aiba playing through the game. Aiba is a popstar and actor - ditto for Ninomiya; however, he's known to Western audiences for his role in Letters from Iwo Jima.
Super Mario Galaxy 2 will be out later this month in Japan and North America. It'll be out in Japan the following month.