Someone asked for links, here are a few:

geodesy: http://pbo.unavco.org/data/gps/realtime

Earth: http://rapidfire.sci.gsfc.nasa.gov/realtime/

space weather: http://www.swpc.noaa.gov/SWN/

time-domain astronomy: http://voeventnet.caltech.edu/feeds/Catalina.shtml

The last one is pretty neat. It contains an XML event summary that can be used to target a telescope automatically, if you think that event is of interest to you. The events are automatically found by an image-processing front end which taps into a near-earth-objects survey. In other words, they did the hard work already to find unexplained brightness variations.