Look, if you can actually use these apps, you've already spent a few hundred dollars (at least) on the required hardware: an iPhone and an iPad. Buying a real dartboard would definitely be cheaper. But that does nothing to offset the fact that the KL Dartboard looks really, really cool.
The KL Dartboard app for iPad transforms your device into a giant, glossy-screened dartboard; meanwhile, the KL Darts app for iPhone "holds" your darts. The two apps connect using Bluetooth—no internet connection requires—and then you aim your iPhone at your new dartboard, give it a quick shake, and watch as your dart is "thrown" from your iPhone and onto your iPad. The apps use accelerometer data from the iPhone to determine where you're aiming. KL Dartboard is designed for two players.
We haven't seen too many iPhone/iPad combo apps, though EA's Scrabble Tile Rack for iPhone, which works with the Scrabble app for iPad, remains a good example. It's a shame, really—though obviously the audience is limited, there are still some really nifty concepts that can work with unique combination. There's something bizarrely futuristic about tossing darts from one device to another...only with the iOS, right?
KL Dartboard is available on the App Store for $3.99; KL Darts comes in both free and pro ($0.99) flavors.