If you live in an area where earthquakes happen, or if you just want to track earthquakes around the world, check out QuakeInfo from Atomic Powered. It's a simple thing, really, but a handy way to track earthquakes globally. QuakeInfo uses information from the U.S. Geological Survey to display quakes of magnitude 2.5 or greater within a week.
Check out the video below to see QuakeInfo in action. There's a list view and map view, with the map view allowing you to look for geological trends. Handy if you're predicting the end of days!