Well, I'm not sure about classes on chivalry per se --
but I do know that a lot of our boys' schools (such as "Our Lady of La Salette" in Olivet, IL) do an excellent job of turning boys into young gentlemen. I think St. Marys, KS does a similar good job.
You just soak it up by being in such a good environment. Good manners, respect for women, etc. just grows naturally out of a young man taught to love God and practice charity.
I've met a lot of men that are very polite and would be considered gentlemen.
Matthew