Capital Cities of the USA challenges you. Not only do you need to know the capital city of all 50 states, but you have to know where they are located geographically.
An excellent "learn as you play" app.
This is a try-before-you-buy version which will quiz only 20 states before requiring an in-app purchase. If you are interested in purchasing under the educational institute discount program please see the school version (id: 525759225).