Surf the web
Nintendo isn't as far behind in this area as you might assume. The PS3 has had an internet browser all along, sure, but it's pretty much the worst browser imaginable. And the Xbox 360 only recently got its version of Internet Explorer, and it's not that great either.
With the added convenience of the Wii U's GamePad, which can display a keyboard for easy typing, the Wii U may actually have the best console browser right now. And it's definitely better than the Wii's slow and weird Opera browser.