Android app Solaris uses real-time data from several of NASA's orbital observation satellites, giving you an accurate representation of the magnetic field of the planet. It might come in handy when the apocalypse hits.
According to the maker, the "phone vibrates when geomagnetic storm level rises" which will be quite the conversation starter when your HTC Aria starts buzzing on the table during a meeting. The app also charts solar activity and sunspots via data from NASA's STEREO observer, if you're more of a summer person. [Androidpit]