So there's this "Neighborhood" application on Facebook, where you can say where you live and then find out about others living nearby (who also have this application installed), or something.
Only it doesn't support Germany. At all.
So I asked about that on the application message board, and got a private message telling me that the reason they didn't support Germany was that they didn't have any data for it; they needed structured data country-region-city.
So I thought I'd see what I could find, starting with "Liste deutscher Städte" on Wikipedia -- which, fortunately, existed as a redirect to the real article.
Exported that to a text file and did some normalising (e.g. NRW, Nordrh.-Westf. etc. --> Nordrhein-Westfalen; Landeshauptstadt von Sachsen --> Sachsen), uploaded it to my webspace and pointed the Neighborhood chap at it. Got a message back a day or so later saying that's exactly what they needed and that I should see Germany supported by Thursday or so. Whee!
Two yays, actually: one for telling me they'd add Germany now that they had some structured data, and one for telling me what they needed, or what had prevented them from adding Germany in the past, in the first place, so that I didn't just have to complain but could actually do something about it.
Or triple yay: yay for Wikipedia having an easily extractable source of the data I was looking for.