Typing away at your desk just got way more fun. The iSeismometer app turns your iPhone into a seismometer, detecting vibrations in real time. The app can store up to 10 seconds of data, and advanced users can go to a free online tutorial for ways to play with that data (pretty graphs, anyone?). The app makes it easy to export the data via Wi-Fi or email.
iSeismometer includes an optional alarm feature to detect sudden movement. Most people will probably just have fun playing around with vibrations from speakers, keyboards and the like, but if you happen to experience a real earthquake while using iSeismometer, the app lets you report the shaking with the tap of a finger.