InfoViz update
I have a pretty good handle on using Google’s GeoCode to get lat/long from my cities. Next, I am plotting them on a map, which Ben Fry provides a pretty good example for. Then, add a date slider. Then, maybe a zoom thing where you can read the sighting text.
Check out this UFO sighting map from the National UFO Reporting Center. It looks like they plot position, time, and shape of the object. If you have more detailed demographic data (who reported? frequency fo reports per person or area, etc), you might be able to pull out some more interesting correlations.