I'd love a test on world leaders: prime ministers, presidents, kings, queens, etc. I realize the test would have to be changed every time there is a new election, etc. but it seems like once it was set up it'd be pretty easy to keep updated.
Neither history nor famous people has a section about CURRENT world leaders, other than one course about important American politicians. I may just have to make my own course on the topic. Learning all the capitals gave me so much motivation to know more!