Webfoot's Election/Demographics Map
Ducky Sherwood has created a Google Map mashup that lets users combine various layers of thematic information related to the US presidential election. Election, demographic, and point layers can be viewd in any combination on the map.
Users of the map can also adjust the colour mapping/opacity of the choropleth layers and size/colour of the points layer. The different layers feature lots and lots of polygons (over 3000) and points (more than 30,000 in one overlay). This is done by generating tiles on the fly, but quickly enough to be usable.