But I must confess that I have practised this a couple of months ago on Sporcle without map and without alphabetical list to remind you of those pesky Caribbean or Pacific islands you accidentally skipped.
Can't remember what the site's name was, but I like the one where they give you a 3D picture of a place on the Earth and you have to guess by looking around where it is. Then they take the distance from where you guessed to where it really is and that's how you keep score. Lowest score wins. Can't really cheat on this one either (not saying anyone would, of course).
149 out of 196 (first try), but yeah about 5 years ago a friend and I pretty much memorized every country and capital and flag. It just started as a simple game, but eventually it became very competitive..
That link by the way says "Quiz Not Found", but I also remember another site where you could also memorize the flags of each country. If I am bored maybe I try to get my skill level back to 100% :P
I attempted this during a conference call at work and got interrupted with about 7 minutes remaining. 130/196. I was running out of steam anyway, my weak points were central Asia ("stan" countries and their neighbors), west Africa, and the various Pacific islands.