Sullivan Ballou wrote a last letter to his wife a few days before the first Battle of Bull Run. Primary documents are a great way to present any part of US history. Above is the clip from Ken Burn's Civil War documentary and here is a written copy. Here is much more on Ballou and his death.
So in the sprit of the post below, a flipped class might have a screencast on the major battles if the Civil War (Fort Sumter, Bull Run, Shiloh, Antietam, Gettysburg) and then have the students perform an exercise where they look at Ballou's letter and select a battle and write from different perspectives such as the military leaders of the Union or Confederacy, Lincoln's perspective, etc. In such a letter, the students would have to show comprehension of the battles and yet be creative enough to an understanding of what might be coming up or have just passed, if done afterwards.
For such an assignment, you could go to Rubistar and make your own rubric.
All of this was generated from a book I am reading called Dataclysm I guess I am never too far away from my teaching!