There are 195 countries that currently exist in the world (five of them no longer exist, like Crimea or Tibet). There are also five new countries that have only been formed in the last 30 years.
I did this myself three days ago. I was able to name 106 out of 195, which is 54% of the world, without looking. Not too bad. Africa is the hardest region, but East Asia, West Europe, and the Middle East are also pretty difficult. HOW MANY CAN YOU GUESS?
Bonus points and higher chance of getting MHO if you can tell me something about each country.