Reggie Fils-Aime, president of Nintendo of America, went on the Jimmy Fallon show to show off Super Mario Run and to give the first live gameplay demo for the Nintendo Switch. Once Fils-Aime was done showing the new Mario game, he opened a golden cube containing the Switch.
They proceeded to play a little bit of The Legend of Zelda: Breath of the Wild on the console. Fils-Aime eventually demonstrated how players can undock the console and continue playing in a mobile mode.
You can see Super Mario Run, the Nintendo Switch, and the upcoming Zelda title in the included video.