Europe

Hard to believe there are 50 countries in Europe, the same number of states in the US (unless you include the de facto state, Puerto Rico).  It's also interesting to note that Europe is 3.931 million square miles, while the US is 3.794 million square miles -- a difference of less than 4%.  In 2013, the US GDP was $16.7 trillion while the EU (which only accounts for 28 of the 51 countries) was $15.8 trillion.  (In fact, the EU had outperformed the US every year from 2007-2012.)

So the question is, how many European countries can you name?  (Write them down now and then check them off as you go.)

I'm sure you can get the "Big 5."

 Germany
 United Kingdom
 France
 Italy
 Spain

Hopefully you can get the rest of what I'll call "Western Europe."

Netherlands
Belgium
Greece
Portugal
Sweden
Switzerland
Denmark
Finland
Norway
Ireland
Austria
Luxembourg
Iceland

You'd be forgiven if you missed any of the "microstates."

 San Marino
 Andorra
 Malta
 Liechtenstein
 Monaco
 Vatican City (842 citizens in 0.2 square miles!)

"Eastern Europe" gets politically dicey, as I discovered when I visited Prague, which considers itself very much part of "Western Europe."  However, I'll go with the "Cold War" definition of European countries under Soviet influence, either as part of the USSR or a member of the Warsaw Pact. Of course, back then there were only 8 countries; now there are 24!

 Russia
 Ukraine (USSR)
 Poland (Warsaw Pact)
 Romania (Warsaw Pact)
 Czech Republic (Warsaw Pact, as part of Czechoslovakia)
 Hungary (Warsaw Pact)
 Belarus (USSR)
 Bulgaria (Warsaw Pact)
 Slovakia (Warsaw Pact, as part of Czechoslovakia)
 Georgia (USSR)
 Moldova (USSR)
 Lithuania (USSR)
 Latvia (USSR)
 Estonia (USSR)
 Albania (Warsaw Pact)
 Armenia (USSR)
 Azerbaijan (USSR)
 Serbia (part of Yugoslavia)
 Croatia (part of Yugoslavia)
 Slovenia (part of Yugoslavia)
 Macedonia (part of Yugoslavia)
 Montenegro (part of Yugoslavia)
 Bosnia and Herzegovina (part of Yugoslavia)
 Kosovo (part of Yugoslavia) -- not all countries recognise Kosovo, and Serbia claims it

You might not think of Russia as part of Europe, and in fact only a quarter of Russia is in Europe (if you define Europe as "west of the Ural mountains").  However, 77% of its population live in Western Russia (that is, Europe).  Turkey, on the other hand, is only 3% in Europe, and Cyprus isn't in Europe at all, but they are considered European as well!  (A portion of Kazakhstan is west of the Ural river, but is not considered European.)

The odd thing is that no matter how you define Europe, Israel is definitely not in it.  Why then, are they invited to Eurovision every year?  The answer is slightly odd: In 1950, the European Broadcasting Union was created by "public service broadcasters" and they defined the "European Broadcasting Area" to include northern Africa and the Middle East.  As any member can participate, Israel chose to do so, starting in 1973.  However, since Israel participated, the other eligible countries -- Algeria,  Egypt,  Jordan,  Lebanon,  Libya,  Morocco and  Tunisia -- have refused to participate. Their loss...