Sites like Wikipedia and IMDB often provide the country of origin for TV series and movies. It would be nice if they had a way to do that in markup as well. Something like:

{
  "@context": "http://schema.org/",
  "@type": "Movie",
  "name": "Ghostbusters",
  "countryOfOrigin": {
    "@type": "Country",
    "name": "USA"
  }
}

In some cases, there will be more than one country, which is fine. Authors can provide more than one value.