Wow! I found an online game that seems to do the impossible: you can learn and have a bit of fun at the same time.
The game: Abraham Lincoln’s Crossroads
The price: Free
Here is a brief description from the publisher:
The online game is intended for advanced middle- and high-school students. It invites them to learn about Lincoln’s leadership by exploring the political choices he made. An animated Lincoln introduces a situation, asks for advice and prompts players to decide the issue for themselves, before learning the actual outcome. At the end of the game, players discover how frequently they predicted Lincoln’s actions. A Resources Page keyed to each chapter provides links to relevant Websites on Lincoln and the Civil War, permitting students to explore issues in more depth.
The game is based on the National Constitution Center’s traveling exhibit Lincoln: The Constitution & the Civil War. They have graciously agreed to host the game, free of charge on their website.