I have had a bit of fun the last couple of days with the Jet Punk world quiz, where you have 12 minutes to name all 196 nations of the world (officially there are 195, but they count Taiwan as a sovereign nation. That’s an interesting political issue that I won’t be going into.) Any places/nations that are territories of a sovereign nation (for example, French Guiana, Greenland) don’t count, and it’s the UK, not Scotland, England, Wales, Northern Ireland.
I found that my weak spots were Africa and Eastern Europe, but after lots of drills, I am able to get all 196, which includes the small city states of the world (like Vatican City.)
There is also the 50 United States challenge- keep in mind, if you read the comments, that most Americans memorise these at primary school.
And for the crazies: World capitals Quiz.