For those who are unaware sites like
gutenberg.org,
archive.org, and
panda.cd (although I really haven't checked out panda.cd much) offer free
legal and public domain content (ebooks, music, videos, ect). Most of it is not all that amazing, but there are some decent works hidden in there. So far I havn't done much browsing, but the various field manual archives caught my eye (
https://archive.org/details/field-technical-manuals). Care to share any of your findings?