The Mercator projection can be useful for giving directions, but when it comes to world maps, the projection doesn’t hold up well as you move far north and south. By how much? Give this puzzle game a try and match the red boundaries to their respective countries.
Mercator map puzzle
Here’s a more dynamic version, giving you 15 different countries on each refresh: http://bramus.github.com/mercator-puzzle-redux/
Just in case you get stuck with any particular country, its pretty easy to just view source and find the countries based on the variable names.