Lego's augmented reality Playgrounds app was arguably the highlight of the demos at Apple's yearly developer conference, and now you can try it for yourself -- the iOS app is available today. Point your iPad or iPhone at a compatible Lego set (more on that in a bit) while you're using the app and you'll see bricks liven up with animations, interactive moments and full-fledged games. You'll have a strong incentive to complete a set besides the usual opportunities for imaginative play.
There's only one initial experience, but it's at least a popular one. "Selected" Ninjago sets (currently the Dieselnaut and Dragon's Pit packs) let you battle against waves of Dragon Hunters, either by yourself or with a friend toting their own iOS device. And if you don't have a set, you're not completely out of luck. So long as you can find a flat surface, you can play five levels brick-free.
The app is free, and importantly won't include in-app purchases or sales pitches. Not that Lego needs to charge. It knows Playgrounds only really comes alive if you buy its sets, so it can afford to give away the app knowing you'll likely pay something.