When your 3DS is connected to a Nintendo Zone, you can watch 3D videos of game previews, play demos, play triva games, and view full-length animations. If you take your Nintendo 3DS out and about with you, and you happen to stumble on a Nintendo Zone, your 3DS will alert you with a message on its touch screen. Tap the "Nintendo Zone" icon on your Home screen to see what you can access (if you don't see the Nintendo Zone icon on your Home screen, you might need to perform a system update).
Occasionally, Nintendo teams up with retailers like Best Buy and utilizes Nintendo Zones to host exclusive game deals. In these instances, you can download a bar code that offers price discounts, or other great offers. Typically, Nintendo doesn't publicize what's going on sale, or where, so it pays to carry around your 3DS and see what's new!
When you're connected to a Nintendo Zone, you can also do all the cool stuff that you can typically do with a Nintendo 3DS and a Wi-Fi connection. This includes browsing for and downloading games at the eShop, downloading videos and other content via SpotPass, and playing select multiplayer titles against friends. You should also be able to download game demos from the eShop, which is a handy way of sampling a game before buying it if you happen to be in or near a game store.
In order to access a Nintendo Zone, your Nintendo 3DS's internet connection must be activated.
Nintendo has a Nintendo Zone hotspot locator on its website. There are currently over 29,000 hotspots available. Check and see if one is near you!