Wii Sports is now available on the Wii U eShop as Wii Sports Club. Albeit only with Tennis and Bowling, with the HD port due to add Boxing, Baseball, and Golf in the "months ahead," last we heard.
In addition to hi-def sprucing and Wii MotionPlus support (you'll need the MotionPlus add-on or a Wii Remote Plus to play), Club brings online versus mulitplayer to the Wii Sports experience. Players can tie themselves to regional clubs, and increase their club ranking by taking on members of rival clubs.
Unlike the original game, which came bundled with the Wii, there are a couple of pricing models to get your head round with Wii Sports Club. You can either purchase a $2 Day Pass, which lets you play all available sports across a 24-hour period, or you can get permanent access to a single sport for $10. In simpler terms, you can effectively unlock the full game of five sports for $50.
If you'd prefer to just check out the Club first, there's a 24-hour trial period that activates when you first start up the game. I had a quick go this morning, and both Bowling and Tennis worked well online, with games easy to set up and without noticeable lag.
For the record, I was excruciatingly awful at Bowling (double figures, people), but I thwacked my way to a superb Tennis victory of 7-4. And now I need a lie down.