Augmented reality (AR) apps that display computer-generated information over a live-video image are a natural for the iPad. And if you're fond of watching the skies, Star Walk is among the best AR apps out there. Where's the International Space Station right now? What's that constellation in the night sky? Point your iPad at the sky, and Star Walk labels the satellites, stars, and constellations on the tablet's display. Since the app doesn't require an Internet connection, it should work just fine when you're out in the wilderness--a boon for urban stargazers seeking to escape nighttime light pollution.