The theme is "medical school content". So the range of topics is pretty wide, but has to be something that medical school, nursing school, or pharmacy school students are learning or going to learn. Many ideas for these games are going to have a game framework that could potentially house almost unlimited educational content. You may want to work on the framework first--then find appropriate subject matter to embed, such as anatomy facts, biochem facts, cardiology facts, facts of diabetes... OR you could find a small medical subject and to build the game around, like a sim game of laparoscopic surgery or placing a central line.