I posted a couple months ago about the Revolutionary War battle projects my students were working on. Well, I have now adapted that same project to go with the Civil War. The best thing about this project is that it is mostly an independent project - it's great to do with a sub.
I have included this list of 15 battles. You can cut up these slips to assign battles to your students.
After students do their research in the computer lab, they work on designing a battle poster using the information from their research.