The Internet Library has a tremendous number of movies, books, software, music, and more for free. Public domain materials are helpful when you are adding engaging information to your courses, or just for broadening your own interests. Go ahead and get your free Internet Library card and start building your own resources.
The Internet has made tremendous strides in communication over the last decade, some of my favorites are the online courses available for FREE. What started with a few Universities that offered select courses, quickly spread into many Universities and Colleges preparing online courses for people to take if they wanted to. Now the offerings are vast, and the ability to earn validated certificates or specializations in fields are increasing. If you have never considered entering into the world of MOOC's (Massive Open Online Courses), here's a place that keeps a pretty extensive list.
There's some great freeware in this link. If you prefer to use the sources that are open to public transformation for education and instruction, you will be interested in bookmarking this link for yourself.