I would like to write about two things:
1) On the Všemi osmi blog I found the Traveler IQ challenge - How well do you know your world? link. I passed 10th level of 12 and I think it is good. Last levels was very difficult and I was satisfied if I specified the right continent at least.
2) With the Traveler IQ challenge I remember the World 66 where you can mark your visited countries.