Ask HN: What kind of data would you like to see on a map?

and are the data publicly available?

I've built a new web mapping API and I'm looking for data that I can use to make interesting examples with. Disclaimer: I want to use these examples to attract people's attention to the API and hopefully convert them into paying customers.

I can only make choropleth maps (shaded polygons, election maps, etc) that overlay on Google Maps (or others soon). However, I can render in realtime hundreds of thousands of polygons client side with bring the browser to a crawl.

So any map ideas that are interactive or leverage streaming data would be cool. Or perhaps no one likes maps?