We have about 100 fiberglass Eames chairs in our corporate museum, as seen in the photo above. The chairs had been used by Sullins College and we inherited them when we purchased the campus of the bankrupt school and moved our headquarters there in the late '70s. The beauty is in the stacking feature, so they take up considerably less room.
We use them for meetings and parties. They are surprisingly comfortable. Ours are "Red Orange" (we also have a few in "Greige"), as seen in this color swatch from a 1962 Herman Miller illustrated price list) and tentatively date from the 1960s, although they could have been produced a little later.
Eames stacking fiberglass shell chairs can be found on ebay in a variety of colors and would be great for a desk chair in your home office. Or buy a few and stack them in your garage to use for your next party!