I'm assuming they're probably 8th graders?
Since this was the first war in which photography played a large part & people could actually view pictures from the front in the newspapers, that might be an intersting topic to explore as seeing an actual face makes it so much more real for the kids than seeing a painting of Washington crossing the Delaware. You could collect some examples of early daguerrotypes online & have the students research & report on what happened to the men in the pictures (in general terms, like try & match them to a battle or a prison or Sherman's March to the Sea, for example), or just have them write a fiction story about the soldier in the picture, using some basic facts you provide. I'm almost positive there is a Mathew Brady collection online at the Library of Congress site.
It was also one of the first conflicts in which the telegraph was widely utilized, so the students could learn Morse Code & write secret messages.
Also the first war in which automatic weapons were used (Gatling gun); you could have them do a timeline of developments in weaponry.
The war had a huge death toll, which might be a good topic for a graphing activity.
You could collect some Civil War soldier recipes & have the kids try some of the simpler ones out if you're brave.
Using Confederate currency, you could do a Math activity on inflation.
Mapping the Underground Railroad, making abolitionist posters, doing a skit about helping runaway slaves.
I had a quick look & ProTeacher actually has a page on this site as well