Who says the data you mash up with Google Maps has to be static? Some of the best hacks are ones where the data is frequently updated, whether it’s daily or by the minute. For an example of the former, see this page tracking the biennial Transpac sailboat race between Long Beach and Honolulu; position reports from each boat are uploaded once daily. For an example of the latter, take a look at this page, which tracks the flight paths of the space shuttle Discovery and the International Space Station (as I write this, they’re docked). The data is updated by the minute: I left the page open and went down for breakfast; when I came back, I had nearly a complete orbit tracked across the map. Neat. (Google Maps Mania: 1, 2)