I wrote last month about getting over to the local living history museum. It's a great way to spend a day outside, getting exercise and learning in one fell swoop.
Traditionally over Memorial Day Weekend our own troup takes a Saturday to go to Sturbridge Village, where we learn about hydro powered mills, tin smithery and of course my personal favorite – fiber processing into cloth, from shearing to weaving.
They have a number of sheep there and they hand shear them, and then clean the wool with amonia and water in large boiling water tubs in the sun. Of course as they are in costume, the women are wearing long dresses and aprons, as well as bonnets, and on a hot day this can be pretty rough, so my first grader gets to see firsthand that she has it pretty cushy when she doesn't have to do this hard work to get her clothing.
They have a mill powered carding machine there that is pushing 300 years of age, there are no synthetic parts on the belt, and the wood of the mechanism is held together with pegs instead of nails. This provides an excellent opportunity to teach about construction methods of long ago, and has amazed many.