Uncharted.fm offers a series of progressively more difficult geography lessons and quizzes. In the beginning you're limited to one region and or continent at a time. As you master each region or continent you earn badges and unlock new challenges.
I really like the manner in which Uncharted.fm presents the lessons. In each lesson you're shown a country, the country's name is read to you, then you practice identifying it in two ways. You identify countries by choosing the name of the country that is highlighted for you. You also identify countries by selecting the one of the three highlighted that match the name you're given.
Applications for Education
Unfortunately, the only way that you can register to use Uncharted.fm is with a Facebook account. If that changes in the future, Uncharted.fm could be a great resource for students to practice identifying the countries of the world.