I posted this before, but I'll mention it again. It went over really well with my kids. I do several things, but the 2 favorites among the kids are when I make hard tack (the night before) so they can taste it. Some actually love it! The other (more educational) activity is making "antique paper" (dip computer paper in strong tea and let dry overnight). The kids write a letter like they're a civil war soldier (or the girls write like they're writing TO a civil war soldier). They have to have the correct date on it, appropriate letter writing skills, and some information in the body of the letter that lets me know they understand the civil war (where they're located, etc...). They did a wonderful job with them. They did a rough draft, then wrote the final copy on the antique paper. It makes a great bulletin board display (in fact, I entered it in the bulletin board contest!).
