In the first year I taught, I had my students play a trading game in which they traded goods between Native Americans and European trading partners. The game was fast-paced, and my students thought they were building trading empires until they discovered their exposure to smallpox and silently spreading that disease around the room. The result was that almost everyone caught smallpox and died. This game helped my students understand how trading assisted in spreading disease, and it made a lasting impression because those students graduated seven years ago. The other day, in the grocery store, one stopped me and asked if I remembered giving them all smallpox and the whole class dying. Games can make a significant impression on students and help them connect to and remember the material. What trading games do you use to effectively teach students about the spread of disease, and what outcomes have you observed in their understanding of the topic?