To mock something fast and loose with geo-json data for the world, this is your fix. Legal status of this dataset: dubious?
You might prefer world-atlas or us-atlas instead, if that is an issue. As a bonus, that will give you not just attributable sources, but topology preservation across features and much smaller files than native geo-json offers. It's the future.
For a good time, drag them to http://bl.ocks.org/1431429 and paint the globe!